source: mainline/uspace/srv/fb/fb.c@ 9446f39

/*
 * Copyright (c) 2008 Martin Decky
 * Copyright (c) 2006 Jakub Vana
 * Copyright (c) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @defgroup fb Graphical framebuffer
 * @brief       HelenOS graphical framebuffer.
 * @ingroup fbs
 * @{
 */

/** @file
 */

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ddi.h>
#include <sysinfo.h>
#include <align.h>
#include <as.h>
#include <ipc/fb.h>
#include <ipc/ipc.h>
#include <ipc/ns.h>
#include <ipc/services.h>
#include <kernel/errno.h>
#include <kernel/genarch/fb/visuals.h>
#include <console/color.h>
#include <console/style.h>
#include <async.h>
#include <bool.h>

#include "font-8x16.h"
#include "fb.h"
#include "main.h"
#include "../console/screenbuffer.h"
#include "ppm.h"

#include "pointer.xbm"
#include "pointer_mask.xbm"

#define DEFAULT_BGCOLOR  0xf0f0f0
#define DEFAULT_FGCOLOR  0x000000

#define MAX_ANIM_LEN     8
#define MAX_ANIMATIONS   4
#define MAX_PIXMAPS      256  /**< Maximum number of saved pixmaps */
#define MAX_VIEWPORTS    128  /**< Viewport is a rectangular area on the screen */

/** Function to render a pixel from a RGB value. */
typedef void (*rgb_conv_t)(void *, uint32_t);

/** Function to draw a glyph. */
typedef void (*dg_t)(unsigned int x, unsigned int y, bool cursor,
    uint8_t *glyphs, uint8_t glyph, uint32_t fg_color, uint32_t bg_color);

struct {
        uint8_t *fb_addr;
        
        unsigned int xres;
        unsigned int yres;
        
        unsigned int scanline;
        unsigned int glyphscanline;
        
        unsigned int pixelbytes;
        unsigned int glyphbytes;
        
        rgb_conv_t rgb_conv;
} screen;

/** Backbuffer character cell. */
typedef struct {
        uint8_t glyph;
        uint32_t fg_color;
        uint32_t bg_color;
} bb_cell_t;

typedef struct {
        bool initialized;
        unsigned int x;
        unsigned int y;
        unsigned int width;
        unsigned int height;
        
        /* Text support in window */
        unsigned int cols;
        unsigned int rows;
        
        /*
         * Style and glyphs for text printing
         */

        /** Current attributes. */
        attr_rgb_t attr;

        /** Pre-rendered mask for rendering glyphs. Different viewports
         * might use different drawing functions depending on whether their
         * scanlines are aligned on a word boundary.*/
        uint8_t *glyphs;

        uint8_t *bgpixel;

        /** Glyph drawing function for this viewport. */
        dg_t dglyph;
        
        /* Auto-cursor position */
        bool cursor_active;
        unsigned int cur_col;
        unsigned int cur_row;
        bool cursor_shown;
        
        /* Back buffer */
        bb_cell_t *backbuf;
        unsigned int bbsize;
} viewport_t;

typedef struct {
        bool initialized;
        bool enabled;
        unsigned int vp;
        
        unsigned int pos;
        unsigned int animlen;
        unsigned int pixmaps[MAX_ANIM_LEN];
} animation_t;

static animation_t animations[MAX_ANIMATIONS];
static bool anims_enabled;

typedef struct {
        unsigned int width;
        unsigned int height;
        uint8_t *data;
} pixmap_t;

static pixmap_t pixmaps[MAX_PIXMAPS];
static viewport_t viewports[128];

static bool client_connected = false;  /**< Allow only 1 connection */

static uint32_t color_table[16] = {
        [COLOR_BLACK]           = 0x000000,
        [COLOR_BLUE]            = 0x0000f0,
        [COLOR_GREEN]           = 0x00f000,
        [COLOR_CYAN]            = 0x00f0f0,
        [COLOR_RED]             = 0xf00000,
        [COLOR_MAGENTA]         = 0xf000f0,
        [COLOR_YELLOW]          = 0xf0f000,
        [COLOR_WHITE]           = 0xf0f0f0,

        [8 + COLOR_BLACK]       = 0x000000,
        [8 + COLOR_BLUE]        = 0x0000ff,
        [8 + COLOR_GREEN]       = 0x00ff00,
        [8 + COLOR_CYAN]        = 0x00ffff,
        [8 + COLOR_RED]         = 0xff0000,
        [8 + COLOR_MAGENTA]     = 0xff00ff,
        [8 + COLOR_YELLOW]      = 0xffff00,
        [8 + COLOR_WHITE]       = 0xffffff,
};

static int rgb_from_attr(attr_rgb_t *rgb, const attrs_t *a);
static int rgb_from_style(attr_rgb_t *rgb, int style);
static int rgb_from_idx(attr_rgb_t *rgb, ipcarg_t fg_color,
    ipcarg_t bg_color, ipcarg_t flags);

static int fb_set_color(viewport_t *vport, ipcarg_t fg_color,
    ipcarg_t bg_color, ipcarg_t attr);

static void draw_glyph_aligned(unsigned int x, unsigned int y, bool cursor,
    uint8_t *glyphs, uint8_t glyph, uint32_t fg_color, uint32_t bg_color);
static void draw_glyph_fallback(unsigned int x, unsigned int y, bool cursor,
    uint8_t *glyphs, uint8_t glyph, uint32_t fg_color, uint32_t bg_color);

static void draw_vp_glyph(viewport_t *vport, bool cursor, unsigned int col,
    unsigned int row);


#define RED(x, bits)                 ((x >> (8 + 8 + 8 - bits)) & ((1 << bits) - 1))
#define GREEN(x, bits)               ((x >> (8 + 8 - bits)) & ((1 << bits) - 1))
#define BLUE(x, bits)                ((x >> (8 - bits)) & ((1 << bits) - 1))

#define COL2X(col)                   ((col) * FONT_WIDTH)
#define ROW2Y(row)                   ((row) * FONT_SCANLINES)

#define X2COL(x)                     ((x) / FONT_WIDTH)
#define Y2ROW(y)                     ((y) / FONT_SCANLINES)

#define FB_POS(x, y)                 ((y) * screen.scanline + (x) * screen.pixelbytes)
#define BB_POS(vport, col, row)      ((row) * vport->cols + (col))
#define GLYPH_POS(glyph, y, cursor)  (((glyph) + (cursor) * FONT_GLYPHS) * screen.glyphbytes + (y) * screen.glyphscanline)


/** ARGB 8:8:8:8 conversion
 *
 */
static void rgb_0888(void *dst, uint32_t rgb)
{
        *((uint32_t *) dst) = rgb & 0xffffff;
}


/** ABGR 8:8:8:8 conversion
 *
 */
static void bgr_0888(void *dst, uint32_t rgb)
{
        *((uint32_t *) dst)
            = (BLUE(rgb, 8) << 16) | (GREEN(rgb, 8) << 8) | RED(rgb, 8);
}


/** RGB 8:8:8 conversion
 *
 */
static void rgb_888(void *dst, uint32_t rgb)
{
        ((uint8_t *) dst)[0] = BLUE(rgb, 8);
        ((uint8_t *) dst)[1] = GREEN(rgb, 8);
        ((uint8_t *) dst)[2] = RED(rgb, 8);
}


/** BGR 8:8:8 conversion
 *
 */
static void bgr_888(void *dst, uint32_t rgb)
{
        ((uint8_t *) dst)[0] = RED(rgb, 8);
        ((uint8_t *) dst)[1] = GREEN(rgb, 8);
        ((uint8_t *) dst)[2] = BLUE(rgb, 8);
}


/** RGB 5:5:5 conversion
 *
 */
static void rgb_555(void *dst, uint32_t rgb)
{
        *((uint16_t *) dst)
            = (RED(rgb, 5) << 10) | (GREEN(rgb, 5) << 5) | BLUE(rgb, 5);
}


/** RGB 5:6:5 conversion
 *
 */
static void rgb_565(void *dst, uint32_t rgb)
{
        *((uint16_t *) dst)
            = (RED(rgb, 5) << 11) | (GREEN(rgb, 6) << 5) | BLUE(rgb, 5);
}


/** RGB 3:2:3
 *
 */
static void rgb_323(void *dst, uint32_t rgb)
{
        *((uint8_t *) dst)
            = ~((RED(rgb, 3) << 5) | (GREEN(rgb, 2) << 3) | BLUE(rgb, 3));
}

/** Draw a filled rectangle.
 *
 * @note Need real implementation that does not access VRAM twice.
 */
static void draw_filled_rect(unsigned int x0, unsigned int y0, unsigned int x1,
    unsigned int y1, uint32_t color)
{
        unsigned int x, y;
        unsigned int copy_bytes;

        uint8_t *sp, *dp;
        uint8_t cbuf[4];

        if (y0 >= y1 || x0 >= x1) return;
        screen.rgb_conv(cbuf, color);

        sp = &screen.fb_addr[FB_POS(x0, y0)];
        dp = sp;

        /* Draw the first line. */
        for (x = x0; x < x1; x++) {
                memcpy(dp, cbuf, screen.pixelbytes);
                dp += screen.pixelbytes;
        }

        dp = sp + screen.scanline;
        copy_bytes = (x1 - x0) * screen.pixelbytes;

        /* Draw the remaining lines by copying. */
        for (y = y0 + 1; y < y1; y++) {
                memcpy(dp, sp, copy_bytes);
                dp += screen.scanline;
        }
}

/** Redraw viewport.
 *
 * @param vport Viewport to redraw
 *
 */
static void vport_redraw(viewport_t *vport)
{
        unsigned int row, col;

        for (row = 0; row < vport->rows; row++) {
                for (col = 0; col < vport->cols; col++) {
                        draw_vp_glyph(vport, false, col, row);
                }
        }

        if (COL2X(vport->cols) < vport->width) {
                draw_filled_rect(
                    vport->x + COL2X(vport->cols), vport->y,
                    vport->x + vport->width, vport->y + vport->height,
                    vport->attr.bg_color);
        }

        if (ROW2Y(vport->rows) < vport->height) {
                draw_filled_rect(
                    vport->x, vport->y + ROW2Y(vport->rows),
                    vport->x + vport->width, vport->y + vport->height,
                    vport->attr.bg_color);
        }
}

static void backbuf_clear(bb_cell_t *backbuf, size_t len, uint32_t fg_color,
    uint32_t bg_color)
{
        unsigned i;

        for (i = 0; i < len; i++) {
                backbuf[i].glyph = 0;
                backbuf[i].fg_color = fg_color;
                backbuf[i].bg_color = bg_color;
        }
}

/** Clear viewport.
 *
 * @param vport Viewport to clear
 *
 */
static void vport_clear(viewport_t *vport)
{
        backbuf_clear(vport->backbuf, vport->cols * vport->rows,
            vport->attr.fg_color, vport->attr.bg_color);
        vport_redraw(vport);
}

/** Scroll viewport by the specified number of lines.
 *
 * @param vport Viewport to scroll
 * @param lines Number of lines to scroll
 *
 */
static void vport_scroll(viewport_t *vport, int lines)
{
        unsigned int row, col;
        unsigned int x, y;
        uint8_t glyph;
        uint32_t fg_color;
        uint32_t bg_color;
        bb_cell_t *bbp, *xbp;

        /*
         * Redraw.
         */

        y = vport->y;
        for (row = 0; row < vport->rows; row++) {
                x = vport->x;
                for (col = 0; col < vport->cols; col++) {
                        if ((row + lines >= 0) && (row + lines < vport->rows)) {
                                xbp = &vport->backbuf[BB_POS(vport, col, row + lines)];
                                bbp = &vport->backbuf[BB_POS(vport, col, row)];

                                glyph = xbp->glyph;
                                fg_color = xbp->fg_color;
                                bg_color = xbp->bg_color;

                                if (bbp->glyph == glyph &&
                                    bbp->fg_color == xbp->fg_color &&
                                    bbp->bg_color == xbp->bg_color) {
                                        x += FONT_WIDTH;
                                        continue;
                                }
                        } else {
                                glyph = 0;
                                fg_color = vport->attr.fg_color;
                                bg_color = vport->attr.bg_color;
                        }

                        (*vport->dglyph)(x, y, false, vport->glyphs, glyph,
                            fg_color, bg_color);
                        x += FONT_WIDTH;
                }
                y += FONT_SCANLINES;
        }

        /*
         * Scroll backbuffer.
         */

        if (lines > 0) {
                memmove(vport->backbuf, vport->backbuf + vport->cols * lines,
                    vport->cols * (vport->rows - lines) * sizeof(bb_cell_t));
                backbuf_clear(&vport->backbuf[BB_POS(vport, 0, vport->rows - lines)],
                    vport->cols * lines, vport->attr.fg_color, vport->attr.bg_color);
        } else {
                memmove(vport->backbuf - vport->cols * lines, vport->backbuf,
                    vport->cols * (vport->rows + lines) * sizeof(bb_cell_t));
                backbuf_clear(vport->backbuf, - vport->cols * lines,
                    vport->attr.fg_color, vport->attr.bg_color);
        }
}

/** Render glyphs
 *
 * Convert glyphs from device independent font
 * description to current visual representation.
 *
 * @param vport Viewport
 *
 */
static void render_glyphs(viewport_t* vport)
{
        unsigned int glyph;
        
        for (glyph = 0; glyph < FONT_GLYPHS; glyph++) {
                unsigned int y;
                
                for (y = 0; y < FONT_SCANLINES; y++) {
                        unsigned int x;
                        
                        for (x = 0; x < FONT_WIDTH; x++) {
                                screen.rgb_conv(&vport->glyphs[GLYPH_POS(glyph, y, false) + x * screen.pixelbytes],
                                    (fb_font[glyph * FONT_SCANLINES + y] & (1 << (7 - x)))
                                    ? 0xffffff : 0x000000);
                                
                                screen.rgb_conv(&vport->glyphs[GLYPH_POS(glyph, y, true) + x * screen.pixelbytes],
                                    (fb_font[glyph * FONT_SCANLINES + y] & (1 << (7 - x)))
                                    ? 0x000000 : 0xffffff);
                        }
                }
        }
        
        screen.rgb_conv(vport->bgpixel, vport->attr.bg_color);
}


/** Create new viewport
 *
 * @param x      Origin of the viewport (x).
 * @param y      Origin of the viewport (y).
 * @param width  Width of the viewport.
 * @param height Height of the viewport.
 *
 * @return New viewport number.
 *
 */
static int vport_create(unsigned int x, unsigned int y,
    unsigned int width, unsigned int height)
{
        unsigned int i;
        
        for (i = 0; i < MAX_VIEWPORTS; i++) {
                if (!viewports[i].initialized)
                        break;
        }
        if (i == MAX_VIEWPORTS)
                return ELIMIT;
        
        unsigned int cols = width / FONT_WIDTH;
        unsigned int rows = height / FONT_SCANLINES;
        unsigned int bbsize = cols * rows * sizeof(bb_cell_t);
        unsigned int glyphsize = 2 * FONT_GLYPHS * screen.glyphbytes;
        unsigned int word_size = sizeof(unsigned long);
        
        bb_cell_t *backbuf = (bb_cell_t *) malloc(bbsize);
        if (!backbuf)
                return ENOMEM;
        
        uint8_t *glyphs = (uint8_t *) malloc(glyphsize);
        if (!glyphs) {
                free(backbuf);
                return ENOMEM;
        }
        
        uint8_t *bgpixel = (uint8_t *) malloc(screen.pixelbytes);
        if (!bgpixel) {
                free(glyphs);
                free(backbuf);
                return ENOMEM;
        }

        backbuf_clear(backbuf, cols * rows, DEFAULT_FGCOLOR, DEFAULT_BGCOLOR);
        memset(glyphs, 0, glyphsize);
        memset(bgpixel, 0, screen.pixelbytes);
        
        viewports[i].x = x;
        viewports[i].y = y;
        viewports[i].width = width;
        viewports[i].height = height;
        
        viewports[i].cols = cols;
        viewports[i].rows = rows;
        
        viewports[i].attr.bg_color = DEFAULT_BGCOLOR;
        viewports[i].attr.fg_color = DEFAULT_FGCOLOR;
        
        viewports[i].glyphs = glyphs;
        viewports[i].bgpixel = bgpixel;

        /*
         * Conditions necessary  to select aligned version:
         *
         *   - word size is divisible by pixelbytes
         *   - cell scanline size is divisible by word size
         *   - cell scanlines are word-aligned
         */
        if ((word_size % screen.pixelbytes) == 0 &&
            (FONT_WIDTH * screen.pixelbytes) % word_size == 0 &&
            (x * screen.pixelbytes) % word_size == 0 &&
            screen.scanline % word_size == 0) {

                viewports[i].dglyph = draw_glyph_aligned;
        } else {
                viewports[i].dglyph = draw_glyph_fallback;
        }

        viewports[i].cur_col = 0;
        viewports[i].cur_row = 0;
        viewports[i].cursor_active = false;
        viewports[i].cursor_shown = false;
        
        viewports[i].bbsize = bbsize;
        viewports[i].backbuf = backbuf;
        
        viewports[i].initialized = true;
        
        render_glyphs(&viewports[i]);
        
        return i;
}


/** Initialize framebuffer as a chardev output device
 *
 * @param addr   Address of the framebuffer
 * @param xres   Screen width in pixels
 * @param yres   Screen height in pixels
 * @param visual Bits per pixel (8, 16, 24, 32)
 * @param scan   Bytes per one scanline
 *
 */
static bool screen_init(void *addr, unsigned int xres, unsigned int yres,
    unsigned int scan, unsigned int visual)
{
        switch (visual) {
        case VISUAL_INDIRECT_8:
                screen.rgb_conv = rgb_323;
                screen.pixelbytes = 1;
                break;
        case VISUAL_RGB_5_5_5:
                screen.rgb_conv = rgb_555;
                screen.pixelbytes = 2;
                break;
        case VISUAL_RGB_5_6_5:
                screen.rgb_conv = rgb_565;
                screen.pixelbytes = 2;
                break;
        case VISUAL_RGB_8_8_8:
                screen.rgb_conv = rgb_888;
                screen.pixelbytes = 3;
                break;
        case VISUAL_BGR_8_8_8:
                screen.rgb_conv = bgr_888;
                screen.pixelbytes = 3;
                break;
        case VISUAL_RGB_8_8_8_0:
                screen.rgb_conv = rgb_888;
                screen.pixelbytes = 4;
                break;
        case VISUAL_RGB_0_8_8_8:
                screen.rgb_conv = rgb_0888;
                screen.pixelbytes = 4;
                break;
        case VISUAL_BGR_0_8_8_8:
                screen.rgb_conv = bgr_0888;
                screen.pixelbytes = 4;
                break;
        default:
                return false;
        }

        screen.fb_addr = (unsigned char *) addr;
        screen.xres = xres;
        screen.yres = yres;
        screen.scanline = scan;
        
        screen.glyphscanline = FONT_WIDTH * screen.pixelbytes;
        screen.glyphbytes = screen.glyphscanline * FONT_SCANLINES;
        
        /* Create first viewport */
        vport_create(0, 0, xres, yres);
        
        return true;
}


/** Draw a glyph, takes advantage of alignment.
 *
 * This version can only be used if the following conditions are met:
 *
 *   - word size is divisible by pixelbytes
 *   - cell scanline size is divisible by word size
 *   - cell scanlines are word-aligned
 *
 * It makes use of the pre-rendered mask to process (possibly) several
 * pixels at once (word size / pixelbytes pixels at a time are processed)
 * making it very fast. Most notably this version is not applicable at 24 bits
 * per pixel.
 *
 * @param x             x coordinate of top-left corner on screen.
 * @param y             y coordinate of top-left corner on screen.
 * @param cursor        Draw glyph with cursor
 * @param glyphs        Pointer to font bitmap.
 * @param glyph         Code of the glyph to draw.
 * @param fg_color      Foreground color.
 * @param bg_color      Backgroudn color.
 */
static void draw_glyph_aligned(unsigned int x, unsigned int y, bool cursor,
    uint8_t *glyphs, uint8_t glyph, uint32_t fg_color, uint32_t bg_color)
{
        unsigned int i, yd;
        unsigned long fg_buf, bg_buf;
        unsigned long *maskp, *dp;
        unsigned long mask;
        unsigned int ww, d_add;

        /*
         * Prepare a pair of words, one filled with foreground-color
         * pattern and the other filled with background-color pattern.
         */
        for (i = 0; i < sizeof(unsigned long) / screen.pixelbytes; i++) {
                screen.rgb_conv(&((uint8_t *)&fg_buf)[i * screen.pixelbytes],
                    fg_color);
                screen.rgb_conv(&((uint8_t *)&bg_buf)[i * screen.pixelbytes],
                    bg_color);
        }


        /* Pointer to the current position in the mask. */
        maskp = (unsigned long *) &glyphs[GLYPH_POS(glyph, 0, cursor)];

        /* Pointer to the current position on the screen. */
        dp = (unsigned long *) &screen.fb_addr[FB_POS(x, y)];

        /* Width of the character cell in words. */
        ww = FONT_WIDTH * screen.pixelbytes / sizeof(unsigned long);

        /* Offset to add when moving to another screen scanline. */
        d_add = screen.scanline - FONT_WIDTH * screen.pixelbytes;

        for (yd = 0; yd < FONT_SCANLINES; yd++) {
                /*
                 * Now process the cell scanline, combining foreground
                 * and background color patters using the pre-rendered mask.
                 */
                for (i = 0; i < ww; i++) {
                        mask = *maskp++;
                        *dp++ = (fg_buf & mask) | (bg_buf & ~mask);
                }

                /* Move to the beginning of the next scanline of the cell. */
                dp = (unsigned long *) ((uint8_t *) dp + d_add);
        }
}

/** Draw a glyph, fallback version.
 *
 * This version does not make use of the pre-rendered mask, it uses
 * the font bitmap directly. It works always, but it is slower.
 *
 * @param x             x coordinate of top-left corner on screen.
 * @param y             y coordinate of top-left corner on screen.
 * @param cursor        Draw glyph with cursor
 * @param glyphs        Pointer to font bitmap.
 * @param glyph         Code of the glyph to draw.
 * @param fg_color      Foreground color.
 * @param bg_color      Backgroudn color.
 */
void draw_glyph_fallback(unsigned int x, unsigned int y, bool cursor,
    uint8_t *glyphs, uint8_t glyph, uint32_t fg_color, uint32_t bg_color)
{
        unsigned int i, j, yd;
        uint8_t fg_buf[4], bg_buf[4];
        uint8_t *dp, *sp;
        unsigned int d_add;
        uint8_t b;

        /* Pre-render 1x the foreground and background color pixels. */
        if (cursor) {
                screen.rgb_conv(fg_buf, bg_color);
                screen.rgb_conv(bg_buf, fg_color);
        } else {
                screen.rgb_conv(fg_buf, fg_color);
                screen.rgb_conv(bg_buf, bg_color);
        }

        /* Pointer to the current position on the screen. */
        dp = (uint8_t *) &screen.fb_addr[FB_POS(x, y)];

        /* Offset to add when moving to another screen scanline. */
        d_add = screen.scanline - FONT_WIDTH * screen.pixelbytes;

        for (yd = 0; yd < FONT_SCANLINES; yd++) {
                /* Byte containing bits of the glyph scanline. */
                b = fb_font[glyph * FONT_SCANLINES + yd];

                for (i = 0; i < FONT_WIDTH; i++) {
                        /* Choose color based on the current bit. */
                        sp = (b & 0x80) ? fg_buf : bg_buf;

                        /* Copy the pixel. */
                        for (j = 0; j < screen.pixelbytes; j++) {
                                *dp++ = *sp++;
                        }

                        /* Move to the next bit. */
                        b = b << 1;
                }
                
                /* Move to the beginning of the next scanline of the cell. */
                dp += d_add;
        }
}

/** Draw glyph at specified position in viewport. 
 *
 * @param vport  Viewport identification
 * @param cursor Draw glyph with cursor
 * @param col    Screen position relative to viewport
 * @param row    Screen position relative to viewport
 *
 */
static void draw_vp_glyph(viewport_t *vport, bool cursor, unsigned int col,
    unsigned int row)
{
        unsigned int x = vport->x + COL2X(col);
        unsigned int y = vport->y + ROW2Y(row);

        uint8_t glyph;
        uint32_t fg_color;
        uint32_t bg_color;
        
        glyph = vport->backbuf[BB_POS(vport, col, row)].glyph;
        fg_color = vport->backbuf[BB_POS(vport, col, row)].fg_color;
        bg_color = vport->backbuf[BB_POS(vport, col, row)].bg_color;

        (*vport->dglyph)(x, y, cursor, vport->glyphs, glyph,
            fg_color, bg_color);
}

/** Hide cursor if it is shown
 *
 */
static void cursor_hide(viewport_t *vport)
{
        if ((vport->cursor_active) && (vport->cursor_shown)) {
                draw_vp_glyph(vport, false, vport->cur_col, vport->cur_row);
                vport->cursor_shown = false;
        }
}


/** Show cursor if cursor showing is enabled
 *
 */
static void cursor_show(viewport_t *vport)
{
        /* Do not check for cursor_shown */
        if (vport->cursor_active) {
                draw_vp_glyph(vport, true, vport->cur_col, vport->cur_row);
                vport->cursor_shown = true;
        }
}


/** Invert cursor, if it is enabled
 *
 */
static void cursor_blink(viewport_t *vport)
{
        if (vport->cursor_shown)
                cursor_hide(vport);
        else
                cursor_show(vport);
}


/** Draw character at given position relative to viewport
 *
 * @param vport  Viewport identification
 * @param c      Character to draw
 * @param col    Screen position relative to viewport
 * @param row    Screen position relative to viewport
 *
 */
static void draw_char(viewport_t *vport, uint8_t c, unsigned int col, unsigned int row)
{
        bb_cell_t *bbp;

        /* Do not hide cursor if we are going to overwrite it */
        if ((vport->cursor_active) && (vport->cursor_shown) &&
            ((vport->cur_col != col) || (vport->cur_row != row)))
                cursor_hide(vport);

        bbp = &vport->backbuf[BB_POS(vport, col, row)];
        bbp->glyph = c;
        bbp->fg_color = vport->attr.fg_color;
        bbp->bg_color = vport->attr.bg_color;

        draw_vp_glyph(vport, false, col, row);
        
        vport->cur_col = col;
        vport->cur_row = row;
        
        vport->cur_col++;
        if (vport->cur_col >= vport->cols) {
                vport->cur_col = 0;
                vport->cur_row++;
                if (vport->cur_row >= vport->rows)
                        vport->cur_row--;
        }
        
        cursor_show(vport);
}


/** Draw text data to viewport
 *
 * @param vport Viewport id
 * @param data  Text data fitting exactly into viewport
 *
 */
static void draw_text_data(viewport_t *vport, keyfield_t *data)
{
        unsigned int i;
        bb_cell_t *bbp;
        attrs_t *a;
        attr_rgb_t rgb;
        
        for (i = 0; i < vport->cols * vport->rows; i++) {
                unsigned int col = i % vport->cols;
                unsigned int row = i / vport->cols;
                
                bbp = &vport->backbuf[BB_POS(vport, col, row)];
                uint8_t glyph = bbp->glyph;

                a = &data[i].attrs;
                rgb_from_attr(&rgb, a);

                bbp->glyph = data[i].character;
                bbp->fg_color = rgb.fg_color;
                bbp->bg_color = rgb.bg_color;

                draw_vp_glyph(vport, false, col, row);
        }
        cursor_show(vport);
}


static void putpixel_pixmap(void *data, unsigned int x, unsigned int y, uint32_t color)
{
        int pm = *((int *) data);
        pixmap_t *pmap = &pixmaps[pm];
        unsigned int pos = (y * pmap->width + x) * screen.pixelbytes;
        
        screen.rgb_conv(&pmap->data[pos], color);
}


static void putpixel(void *data, unsigned int x, unsigned int y, uint32_t color)
{
        viewport_t *vport = (viewport_t *) data;
        unsigned int dx = vport->x + x;
        unsigned int dy = vport->y + y;
        
        screen.rgb_conv(&screen.fb_addr[FB_POS(dx, dy)], color);
}


/** Return first free pixmap
 *
 */
static int find_free_pixmap(void)
{
        unsigned int i;
        
        for (i = 0; i < MAX_PIXMAPS; i++)
                if (!pixmaps[i].data)
                        return i;
        
        return -1;
}


/** Create a new pixmap and return appropriate ID
 *
 */
static int shm2pixmap(unsigned char *shm, size_t size)
{
        int pm;
        pixmap_t *pmap;
        
        pm = find_free_pixmap();
        if (pm == -1)
                return ELIMIT;
        
        pmap = &pixmaps[pm];
        
        if (ppm_get_data(shm, size, &pmap->width, &pmap->height))
                return EINVAL;
        
        pmap->data = malloc(pmap->width * pmap->height * screen.pixelbytes);
        if (!pmap->data)
                return ENOMEM;
        
        ppm_draw(shm, size, 0, 0, pmap->width, pmap->height, putpixel_pixmap, (void *) &pm);
        
        return pm;
}


/** Handle shared memory communication calls
 *
 * Protocol for drawing pixmaps:
 * - FB_PREPARE_SHM(client shm identification)
 * - IPC_M_AS_AREA_SEND
 * - FB_DRAW_PPM(startx, starty)
 * - FB_DROP_SHM
 *
 * Protocol for text drawing
 * - IPC_M_AS_AREA_SEND
 * - FB_DRAW_TEXT_DATA
 *
 * @param callid Callid of the current call
 * @param call   Current call data
 * @param vp     Active viewport
 *
 * @return false if the call was not handled byt this function, true otherwise
 *
 * Note: this function is not threads safe, you would have
 * to redefine static variables with __thread
 *
 */
static bool shm_handle(ipc_callid_t callid, ipc_call_t *call, int vp)
{
        static keyfield_t *interbuffer = NULL;
        static size_t intersize = 0;
        
        static unsigned char *shm = NULL;
        static ipcarg_t shm_id = 0;
        static size_t shm_size;
        
        bool handled = true;
        int retval = EOK;
        viewport_t *vport = &viewports[vp];
        unsigned int x;
        unsigned int y;
        
        switch (IPC_GET_METHOD(*call)) {
        case IPC_M_SHARE_OUT:
                /* We accept one area for data interchange */
                if (IPC_GET_ARG1(*call) == shm_id) {
                        void *dest = as_get_mappable_page(IPC_GET_ARG2(*call));
                        shm_size = IPC_GET_ARG2(*call);
                        if (!ipc_answer_1(callid, EOK, (sysarg_t) dest))
                                shm = dest;
                        else
                                shm_id = 0;
                        
                        if (shm[0] != 'P')
                                return false;
                        
                        return true;
                } else {
                        intersize = IPC_GET_ARG2(*call);
                        receive_comm_area(callid, call, (void *) &interbuffer);
                }
                return true;
        case FB_PREPARE_SHM:
                if (shm_id)
                        retval = EBUSY;
                else 
                        shm_id = IPC_GET_ARG1(*call);
                break;
                
        case FB_DROP_SHM:
                if (shm) {
                        as_area_destroy(shm);
                        shm = NULL;
                }
                shm_id = 0;
                break;
                
        case FB_SHM2PIXMAP:
                if (!shm) {
                        retval = EINVAL;
                        break;
                }
                retval = shm2pixmap(shm, shm_size);
                break;
        case FB_DRAW_PPM:
                if (!shm) {
                        retval = EINVAL;
                        break;
                }
                x = IPC_GET_ARG1(*call);
                y = IPC_GET_ARG2(*call);
                
                if ((x > vport->width) || (y > vport->height)) {
                        retval = EINVAL;
                        break;
                }
                
                ppm_draw(shm, shm_size, IPC_GET_ARG1(*call),
                    IPC_GET_ARG2(*call), vport->width - x, vport->height - y, putpixel, (void *) vport);
                break;
        case FB_DRAW_TEXT_DATA:
                if (!interbuffer) {
                        retval = EINVAL;
                        break;
                }
                if (intersize < vport->cols * vport->rows * sizeof(*interbuffer)) {
                        retval = EINVAL;
                        break;
                }
                draw_text_data(vport, interbuffer);
                break;
        default:
                handled = false;
        }
        
        if (handled)
                ipc_answer_0(callid, retval);
        return handled;
}


static void copy_vp_to_pixmap(viewport_t *vport, pixmap_t *pmap)
{
        unsigned int width = vport->width;
        unsigned int height = vport->height;
        
        if (width + vport->x > screen.xres)
                width = screen.xres - vport->x;
        if (height + vport->y > screen.yres)
                height = screen.yres - vport->y;
        
        unsigned int realwidth = pmap->width <= width ? pmap->width : width;
        unsigned int realheight = pmap->height <= height ? pmap->height : height;
        
        unsigned int srcrowsize = vport->width * screen.pixelbytes;
        unsigned int realrowsize = realwidth * screen.pixelbytes;
        
        unsigned int y;
        for (y = 0; y < realheight; y++) {
                unsigned int tmp = (vport->y + y) * screen.scanline + vport->x * screen.pixelbytes;
                memcpy(pmap->data + srcrowsize * y, screen.fb_addr + tmp, realrowsize);
        }
}


/** Save viewport to pixmap
 *
 */
static int save_vp_to_pixmap(viewport_t *vport)
{
        int pm;
        pixmap_t *pmap;
        
        pm = find_free_pixmap();
        if (pm == -1)
                return ELIMIT;
        
        pmap = &pixmaps[pm];
        pmap->data = malloc(screen.pixelbytes * vport->width * vport->height);
        if (!pmap->data)
                return ENOMEM;
        
        pmap->width = vport->width;
        pmap->height = vport->height;
        
        copy_vp_to_pixmap(vport, pmap);
        
        return pm;
}


/** Draw pixmap on screen
 *
 * @param vp Viewport to draw on
 * @param pm Pixmap identifier
 *
 */
static int draw_pixmap(int vp, int pm)
{
        pixmap_t *pmap = &pixmaps[pm];
        viewport_t *vport = &viewports[vp];
        
        unsigned int width = vport->width;
        unsigned int height = vport->height;
        
        if (width + vport->x > screen.xres)
                width = screen.xres - vport->x;
        if (height + vport->y > screen.yres)
                height = screen.yres - vport->y;
        
        if (!pmap->data)
                return EINVAL;
        
        unsigned int realwidth = pmap->width <= width ? pmap->width : width;
        unsigned int realheight = pmap->height <= height ? pmap->height : height;
        
        unsigned int srcrowsize = vport->width * screen.pixelbytes;
        unsigned int realrowsize = realwidth * screen.pixelbytes;
        
        unsigned int y;
        for (y = 0; y < realheight; y++) {
                unsigned int tmp = (vport->y + y) * screen.scanline + vport->x * screen.pixelbytes;
                memcpy(screen.fb_addr + tmp, pmap->data + y * srcrowsize, realrowsize);
        }
        
        return EOK;
}


/** Tick animation one step forward
 *
 */
static void anims_tick(void)
{
        unsigned int i;
        static int counts = 0;
        
        /* Limit redrawing */
        counts = (counts + 1) % 8;
        if (counts)
                return;

        for (i = 0; i < MAX_ANIMATIONS; i++) {
                if ((!animations[i].animlen) || (!animations[i].initialized) ||
                    (!animations[i].enabled))
                        continue;
                
                draw_pixmap(animations[i].vp, animations[i].pixmaps[animations[i].pos]);
                animations[i].pos = (animations[i].pos + 1) % animations[i].animlen;
        }
}


static unsigned int pointer_x;
static unsigned int pointer_y;
static bool pointer_shown, pointer_enabled;
static int pointer_vport = -1;
static int pointer_pixmap = -1;


static void mouse_show(void)
{
        int i, j;
        int visibility;
        int color;
        int bytepos;
        
        if ((pointer_shown) || (!pointer_enabled))
                return;
        
        /* Save image under the pointer. */
        if (pointer_vport == -1) {
                pointer_vport = vport_create(pointer_x, pointer_y, pointer_width, pointer_height);
                if (pointer_vport < 0)
                        return;
        } else {
                viewports[pointer_vport].x = pointer_x;
                viewports[pointer_vport].y = pointer_y;
        }
        
        if (pointer_pixmap == -1)
                pointer_pixmap = save_vp_to_pixmap(&viewports[pointer_vport]);
        else
                copy_vp_to_pixmap(&viewports[pointer_vport], &pixmaps[pointer_pixmap]);
        
        /* Draw mouse pointer. */
        for (i = 0; i < pointer_height; i++)
                for (j = 0; j < pointer_width; j++) {
                        bytepos = i * ((pointer_width - 1) / 8 + 1) + j / 8;
                        visibility = pointer_mask_bits[bytepos] &
                            (1 << (j % 8));
                        if (visibility) {
                                color = pointer_bits[bytepos] &
                                    (1 << (j % 8)) ? 0 : 0xffffff;
                                if (pointer_x + j < screen.xres && pointer_y +
                                    i < screen.yres)
                                        putpixel(&viewports[0], pointer_x + j,
                                            pointer_y + i, color);
                        }
                }
        pointer_shown = 1;
}


static void mouse_hide(void)
{
        /* Restore image under the pointer. */
        if (pointer_shown) {
                draw_pixmap(pointer_vport, pointer_pixmap);
                pointer_shown = 0;
        }
}


static void mouse_move(unsigned int x, unsigned int y)
{
        mouse_hide();
        pointer_x = x;
        pointer_y = y;
        mouse_show();
}


static int anim_handle(ipc_callid_t callid, ipc_call_t *call, int vp)
{
        bool handled = true;
        int retval = EOK;
        int i, nvp;
        int newval;
        
        switch (IPC_GET_METHOD(*call)) {
        case FB_ANIM_CREATE:
                nvp = IPC_GET_ARG1(*call);
                if (nvp == -1)
                        nvp = vp;
                if (nvp >= MAX_VIEWPORTS || nvp < 0 ||
                        !viewports[nvp].initialized) {
                        retval = EINVAL;
                        break;
                }
                for (i = 0; i < MAX_ANIMATIONS; i++) {
                        if (!animations[i].initialized)
                                break;
                }
                if (i == MAX_ANIMATIONS) {
                        retval = ELIMIT;
                        break;
                }
                animations[i].initialized = 1;
                animations[i].animlen = 0;
                animations[i].pos = 0;
                animations[i].enabled = 0;
                animations[i].vp = nvp;
                retval = i;
                break;
        case FB_ANIM_DROP:
                i = IPC_GET_ARG1(*call);
                if (i >= MAX_ANIMATIONS || i < 0) {
                        retval = EINVAL;
                        break;
                }
                animations[i].initialized = 0;
                break;
        case FB_ANIM_ADDPIXMAP:
                i = IPC_GET_ARG1(*call);
                if (i >= MAX_ANIMATIONS || i < 0 ||
                        !animations[i].initialized) {
                        retval = EINVAL;
                        break;
                }
                if (animations[i].animlen == MAX_ANIM_LEN) {
                        retval = ELIMIT;
                        break;
                }
                newval = IPC_GET_ARG2(*call);
                if (newval < 0 || newval > MAX_PIXMAPS ||
                        !pixmaps[newval].data) {
                        retval = EINVAL;
                        break;
                }
                animations[i].pixmaps[animations[i].animlen++] = newval;
                break;
        case FB_ANIM_CHGVP:
                i = IPC_GET_ARG1(*call);
                if (i >= MAX_ANIMATIONS || i < 0) {
                        retval = EINVAL;
                        break;
                }
                nvp = IPC_GET_ARG2(*call);
                if (nvp == -1)
                        nvp = vp;
                if (nvp >= MAX_VIEWPORTS || nvp < 0 ||
                        !viewports[nvp].initialized) {
                        retval = EINVAL;
                        break;
                }
                animations[i].vp = nvp;
                break;
        case FB_ANIM_START:
        case FB_ANIM_STOP:
                i = IPC_GET_ARG1(*call);
                if (i >= MAX_ANIMATIONS || i < 0) {
                        retval = EINVAL;
                        break;
                }
                newval = (IPC_GET_METHOD(*call) == FB_ANIM_START);
                if (newval ^ animations[i].enabled) {
                        animations[i].enabled = newval;
                        anims_enabled += newval ? 1 : -1;
                }
                break;
        default:
                handled = 0;
        }
        if (handled)
                ipc_answer_0(callid, retval);
        return handled;
}


/** Handler for messages concerning pixmap handling
 *
 */
static int pixmap_handle(ipc_callid_t callid, ipc_call_t *call, int vp)
{
        bool handled = true;
        int retval = EOK;
        int i, nvp;
        
        switch (IPC_GET_METHOD(*call)) {
        case FB_VP_DRAW_PIXMAP:
                nvp = IPC_GET_ARG1(*call);
                if (nvp == -1)
                        nvp = vp;
                if (nvp < 0 || nvp >= MAX_VIEWPORTS ||
                        !viewports[nvp].initialized) {
                        retval = EINVAL;
                        break;
                }
                i = IPC_GET_ARG2(*call);
                retval = draw_pixmap(nvp, i);
                break;
        case FB_VP2PIXMAP:
                nvp = IPC_GET_ARG1(*call);
                if (nvp == -1)
                        nvp = vp;
                if (nvp < 0 || nvp >= MAX_VIEWPORTS ||
                        !viewports[nvp].initialized)
                        retval = EINVAL;
                else
                        retval = save_vp_to_pixmap(&viewports[nvp]);
                break;
        case FB_DROP_PIXMAP:
                i = IPC_GET_ARG1(*call);
                if (i >= MAX_PIXMAPS) {
                        retval = EINVAL;
                        break;
                }
                if (pixmaps[i].data) {
                        free(pixmaps[i].data);
                        pixmaps[i].data = NULL;
                }
                break;
        default:
                handled = 0;
        }
        
        if (handled)
                ipc_answer_0(callid, retval);
        return handled;
        
}

static int rgb_from_style(attr_rgb_t *rgb, int style)
{
        switch (style) {
        case STYLE_NORMAL:
                rgb->fg_color = color_table[COLOR_BLACK];
                rgb->bg_color = color_table[COLOR_WHITE];
                break;
        case STYLE_EMPHASIS:
                rgb->fg_color = color_table[COLOR_RED];
                rgb->bg_color = color_table[COLOR_WHITE];
                break;
        default:
                return EINVAL;
        }

        return EOK;
}

static int rgb_from_idx(attr_rgb_t *rgb, ipcarg_t fg_color,
    ipcarg_t bg_color, ipcarg_t flags)
{
        fg_color = (fg_color & 7) | ((flags & CATTR_BRIGHT) ? 8 : 0);
        bg_color = (bg_color & 7) | ((flags & CATTR_BRIGHT) ? 8 : 0);

        rgb->fg_color = color_table[fg_color];
        rgb->bg_color = color_table[bg_color];

        return EOK;
}

static int rgb_from_attr(attr_rgb_t *rgb, const attrs_t *a)
{
        int rc;

        switch (a->t) {
        case at_style:
                rc = rgb_from_style(rgb, a->a.s.style);
                break;
        case at_idx:
                rc = rgb_from_idx(rgb, a->a.i.fg_color,
                    a->a.i.bg_color, a->a.i.flags);
                break;
        case at_rgb:
                *rgb = a->a.r;
                rc = EOK;
                break;
        }

        return rc;
}

static int fb_set_style(viewport_t *vport, ipcarg_t style)
{
        return rgb_from_style(&vport->attr, (int) style);
}

static int fb_set_color(viewport_t *vport, ipcarg_t fg_color,
    ipcarg_t bg_color, ipcarg_t flags)
{
        return rgb_from_idx(&vport->attr, fg_color, bg_color, flags);
}

/** Function for handling connections to FB
 *
 */
static void fb_client_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        unsigned int vp = 0;
        viewport_t *vport = &viewports[vp];
        
        if (client_connected) {
                ipc_answer_0(iid, ELIMIT);
                return;
        }
        
        /* Accept connection */
        client_connected = true;
        ipc_answer_0(iid, EOK);
        
        while (true) {
                ipc_callid_t callid;
                ipc_call_t call;
                int retval;
                unsigned int i;
                int scroll;
                uint8_t glyph;
                unsigned int row, col;
                
                if ((vport->cursor_active) || (anims_enabled))
                        callid = async_get_call_timeout(&call, 250000);
                else
                        callid = async_get_call(&call);
                
                mouse_hide();
                if (!callid) {
                        cursor_blink(vport);
                        anims_tick();
                        mouse_show();
                        continue;
                }
                
                if (shm_handle(callid, &call, vp))
                        continue;
                
                if (pixmap_handle(callid, &call, vp))
                        continue;
                
                if (anim_handle(callid, &call, vp))
                        continue;
                
                switch (IPC_GET_METHOD(call)) {
                case IPC_M_PHONE_HUNGUP:
                        client_connected = false;
                        
                        /* Cleanup other viewports */
                        for (i = 1; i < MAX_VIEWPORTS; i++)
                                vport->initialized = false;
                        
                        /* Exit thread */
                        return;
                
                case FB_PUTCHAR:
                        glyph = IPC_GET_ARG1(call);
                        row = IPC_GET_ARG2(call);
                        col = IPC_GET_ARG3(call);
                        
                        if ((col >= vport->cols) || (row >= vport->rows)) {
                                retval = EINVAL;
                                break;
                        }
                        ipc_answer_0(callid, EOK);
                        
                        draw_char(vport, glyph, col, row);
                        
                        /* Message already answered */
                        continue;
                case FB_CLEAR:
                        vport_clear(vport);
                        cursor_show(vport);
                        retval = EOK;
                        break;
                case FB_CURSOR_GOTO:
                        row = IPC_GET_ARG1(call);
                        col = IPC_GET_ARG2(call);
                        
                        if ((col >= vport->cols) || (row >= vport->rows)) {
                                retval = EINVAL;
                                break;
                        }
                        retval = EOK;
                        
                        cursor_hide(vport);
                        vport->cur_col = col;
                        vport->cur_row = row;
                        cursor_show(vport);
                        break;
                case FB_CURSOR_VISIBILITY:
                        cursor_hide(vport);
                        vport->cursor_active = IPC_GET_ARG1(call);
                        cursor_show(vport);
                        retval = EOK;
                        break;
                case FB_GET_CSIZE:
                        ipc_answer_2(callid, EOK, vport->rows, vport->cols);
                        continue;
                case FB_SCROLL:
                        scroll = IPC_GET_ARG1(call);
                        if ((scroll > (int) vport->rows) || (scroll < (-(int) vport->rows))) {
                                retval = EINVAL;
                                break;
                        }
                        cursor_hide(vport);
                        vport_scroll(vport, scroll);
                        cursor_show(vport);
                        retval = EOK;
                        break;
                case FB_VIEWPORT_SWITCH:
                        i = IPC_GET_ARG1(call);
                        if (i >= MAX_VIEWPORTS) {
                                retval = EINVAL;
                                break;
                        }
                        if (!viewports[i].initialized) {
                                retval = EADDRNOTAVAIL;
                                break;
                        }
                        cursor_hide(vport);
                        vp = i;
                        vport = &viewports[vp];
                        cursor_show(vport);
                        retval = EOK;
                        break;
                case FB_VIEWPORT_CREATE:
                        retval = vport_create(IPC_GET_ARG1(call) >> 16,
                            IPC_GET_ARG1(call) & 0xffff,
                            IPC_GET_ARG2(call) >> 16,
                            IPC_GET_ARG2(call) & 0xffff);
                        break;
                case FB_VIEWPORT_DELETE:
                        i = IPC_GET_ARG1(call);
                        if (i >= MAX_VIEWPORTS) {
                                retval = EINVAL;
                                break;
                        }
                        if (!viewports[i].initialized) {
                                retval = EADDRNOTAVAIL;
                                break;
                        }
                        viewports[i].initialized = false;
                        if (viewports[i].glyphs)
                                free(viewports[i].glyphs);
                        if (viewports[i].bgpixel)
                                free(viewports[i].bgpixel);
                        if (viewports[i].backbuf)
                                free(viewports[i].backbuf);
                        retval = EOK;
                        break;
                case FB_SET_STYLE:
                        retval = fb_set_style(vport, IPC_GET_ARG1(call));
                        break;
                case FB_SET_COLOR:
                        retval = fb_set_color(vport, IPC_GET_ARG1(call),
                            IPC_GET_ARG2(call), IPC_GET_ARG3(call));
                        break;
                case FB_SET_RGB_COLOR:
                        vport->attr.fg_color = IPC_GET_ARG1(call);
                        vport->attr.bg_color = IPC_GET_ARG2(call);
                        retval = EOK;
                        break;
                case FB_GET_RESOLUTION:
                        ipc_answer_2(callid, EOK, screen.xres, screen.yres);
                        continue;
                case FB_POINTER_MOVE:
                        pointer_enabled = true;
                        mouse_move(IPC_GET_ARG1(call), IPC_GET_ARG2(call));
                        retval = EOK;
                        break;
                default:
                        retval = ENOENT;
                }
                ipc_answer_0(callid, retval);
        }
}

/** Initialization of framebuffer
 *
 */
int fb_init(void)
{
        async_set_client_connection(fb_client_connection);
        
        void *fb_ph_addr = (void *) sysinfo_value("fb.address.physical");
        unsigned int fb_offset = sysinfo_value("fb.offset");
        unsigned int fb_width = sysinfo_value("fb.width");
        unsigned int fb_height = sysinfo_value("fb.height");
        unsigned int fb_scanline = sysinfo_value("fb.scanline");
        unsigned int fb_visual = sysinfo_value("fb.visual");
        
        unsigned int fbsize = fb_scanline * fb_height;
        void *fb_addr = as_get_mappable_page(fbsize);
        
        if (physmem_map(fb_ph_addr + fb_offset, fb_addr,
            ALIGN_UP(fbsize, PAGE_SIZE) >> PAGE_WIDTH, AS_AREA_READ | AS_AREA_WRITE) != 0)
                return -1;
        
        if (screen_init(fb_addr, fb_width, fb_height, fb_scanline, fb_visual))
                return 0;
        
        return -1;
}

/**
 * @}
 */