source: mainline/uspace/lib/ui/src/entry.c@ d7f7a4a

/*
 * SPDX-FileCopyrightText: 2021 Jiri Svoboda
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

/** @addtogroup libui
 * @{
 */
/**
 * @file Text entry.
 *
 * Currentry text entry is always read-only. It differs from label mostly
 * by its looks.
 */

#include <clipboard.h>
#include <errno.h>
#include <gfx/context.h>
#include <gfx/cursor.h>
#include <gfx/render.h>
#include <gfx/text.h>
#include <macros.h>
#include <stdlib.h>
#include <str.h>
#include <ui/control.h>
#include <ui/paint.h>
#include <ui/entry.h>
#include <ui/ui.h>
#include <ui/window.h>
#include "../private/entry.h"
#include "../private/resource.h"

static void ui_entry_ctl_destroy(void *);
static errno_t ui_entry_ctl_paint(void *);
static ui_evclaim_t ui_entry_ctl_kbd_event(void *, kbd_event_t *);
static ui_evclaim_t ui_entry_ctl_pos_event(void *, pos_event_t *);

enum {
        ui_entry_hpad = 4,
        ui_entry_vpad = 4,
        ui_entry_hpad_text = 1,
        ui_entry_vpad_text = 0,
        ui_entry_cursor_overshoot = 1,
        ui_entry_cursor_width = 2,
        ui_entry_sel_hpad = 0,
        ui_entry_sel_vpad = 2,
        /** Additional amount to scroll to the left after revealing cursor */
        ui_entry_left_scroll_margin = 30
};

/** Text entry control ops */
ui_control_ops_t ui_entry_ops = {
        .destroy = ui_entry_ctl_destroy,
        .paint = ui_entry_ctl_paint,
        .kbd_event = ui_entry_ctl_kbd_event,
        .pos_event = ui_entry_ctl_pos_event
};

/** Create new text entry.
 *
 * @param window UI window
 * @param text Text
 * @param rentry Place to store pointer to new text entry
 * @return EOK on success, ENOMEM if out of memory
 */
errno_t ui_entry_create(ui_window_t *window, const char *text,
    ui_entry_t **rentry)
{
        ui_entry_t *entry;
        errno_t rc;

        entry = calloc(1, sizeof(ui_entry_t));
        if (entry == NULL)
                return ENOMEM;

        rc = ui_control_new(&ui_entry_ops, (void *) entry, &entry->control);
        if (rc != EOK) {
                free(entry);
                return rc;
        }

        entry->text = str_dup(text);
        if (entry->text == NULL) {
                ui_control_delete(entry->control);
                free(entry);
                return ENOMEM;
        }

        entry->window = window;
        entry->halign = gfx_halign_left;
        *rentry = entry;

        return EOK;
}

/** Destroy text entry.
 *
 * @param entry Text entry or @c NULL
 */
void ui_entry_destroy(ui_entry_t *entry)
{
        if (entry == NULL)
                return;

        ui_control_delete(entry->control);
        free(entry);
}

/** Get base control from text entry.
 *
 * @param entry Text entry
 * @return Control
 */
ui_control_t *ui_entry_ctl(ui_entry_t *entry)
{
        return entry->control;
}

/** Set text entry rectangle.
 *
 * @param entry Text entry
 * @param rect New text entry rectangle
 */
void ui_entry_set_rect(ui_entry_t *entry, gfx_rect_t *rect)
{
        entry->rect = *rect;
}

/** Set text entry horizontal text alignment.
 *
 * @param entry Text entry
 * @param halign Horizontal alignment
 */
void ui_entry_set_halign(ui_entry_t *entry, gfx_halign_t halign)
{
        entry->halign = halign;
        ui_entry_scroll_update(entry, true);
        ui_entry_paint(entry);
}

/** Set text entry read-only flag.
 *
 * @param entry Text entry
 * @param read_only True iff entry is to be read-only.
 */
void ui_entry_set_read_only(ui_entry_t *entry, bool read_only)
{
        entry->read_only = read_only;
}

/** Set entry text.
 *
 * @param entry Text entry
 * @param text New entry text
 * @return EOK on success, ENOMEM if out of memory
 */
errno_t ui_entry_set_text(ui_entry_t *entry, const char *text)
{
        char *tcopy;

        tcopy = str_dup(text);
        if (tcopy == NULL)
                return ENOMEM;

        free(entry->text);
        entry->text = tcopy;
        entry->pos = str_size(text);
        entry->sel_start = entry->pos;

        ui_entry_scroll_update(entry, false);
        ui_entry_paint(entry);

        return EOK;
}

/** Get entry text.
 *
 * @return Pointer to entry text.
 */
const char *ui_entry_get_text(ui_entry_t *entry)
{
        return entry->text;
}

/** Paint cursor.
 *
 * @param entry Text entry
 * @param pos Cursor position (top-left corner of next character)
 * @return EOK on success or an error code
 */
static errno_t ui_entry_paint_cursor(ui_entry_t *entry, gfx_coord2_t *pos)
{
        ui_resource_t *res;
        gfx_rect_t rect;
        gfx_font_metrics_t metrics;
        errno_t rc;

        res = ui_window_get_res(entry->window);

        if (res->textmode) {
                rc = gfx_cursor_set_pos(res->gc, pos);
                return rc;
        }

        gfx_font_get_metrics(res->font, &metrics);

        rect.p0.x = pos->x;
        rect.p0.y = pos->y - ui_entry_cursor_overshoot;
        rect.p1.x = pos->x + ui_entry_cursor_width;
        rect.p1.y = pos->y + metrics.ascent + metrics.descent + 1 +
            ui_entry_cursor_overshoot;

        rc = gfx_set_color(res->gc, res->entry_fg_color);
        if (rc != EOK)
                goto error;

        rc = gfx_fill_rect(res->gc, &rect);
        if (rc != EOK)
                goto error;

        return EOK;
error:
        return rc;
}

/** Return width of text before cursor.
 *
 * @param entry Text entry
 * @return Widht of text before cursor
 */
static gfx_coord_t ui_entry_lwidth(ui_entry_t *entry)
{
        ui_resource_t *res;
        uint8_t tmp;
        gfx_coord_t width;

        res = ui_window_get_res(entry->window);

        tmp = entry->text[entry->pos];

        entry->text[entry->pos] = '\0';
        width = gfx_text_width(res->font, entry->text);
        entry->text[entry->pos] = tmp;

        return width;
}

/** Paint text entry.
 *
 * @param entry Text entry
 * @return EOK on success or an error code
 */
errno_t ui_entry_paint(ui_entry_t *entry)
{
        ui_resource_t *res;
        ui_entry_geom_t geom;
        gfx_text_fmt_t fmt;
        gfx_coord2_t pos;
        gfx_text_fmt_t cfmt;
        gfx_coord2_t cpos;
        gfx_rect_t inside;
        unsigned off1, off2;
        gfx_rect_t sel;
        char c;
        errno_t rc;

        res = ui_window_get_res(entry->window);

        ui_entry_get_geom(entry, &geom);

        if (res->textmode == false) {
                /* Paint inset frame */
                rc = ui_paint_inset_frame(res, &entry->rect, &inside);
                if (rc != EOK)
                        goto error;
        } else {
                inside = entry->rect;
        }

        /* Paint entry background */

        rc = gfx_set_color(res->gc, res->entry_bg_color);
        if (rc != EOK)
                goto error;

        rc = gfx_fill_rect(res->gc, &inside);
        if (rc != EOK)
                goto error;

        pos = geom.text_pos;

        gfx_text_fmt_init(&fmt);
        fmt.font = res->font;
        fmt.color = res->entry_fg_color;
        fmt.halign = gfx_halign_left;
        fmt.valign = gfx_valign_top;

        rc = gfx_set_clip_rect(res->gc, &inside);
        if (rc != EOK)
                goto error;

        off1 = min(entry->pos, entry->sel_start);
        off2 = max(entry->pos, entry->sel_start);

        /* Render initial segment before start of selection */
        c = entry->text[off1];
        entry->text[off1] = '\0';

        rc = gfx_puttext(&pos, &fmt, entry->text);
        if (rc != EOK) {
                (void) gfx_set_clip_rect(res->gc, NULL);
                goto error;
        }

        gfx_text_cont(&pos, &fmt, entry->text, &cpos, &cfmt);
        entry->text[off1] = c;

        /* Render selected text */

        if (off1 != off2) {
                c = entry->text[off2];
                entry->text[off2] = '\0';
                cfmt.color = res->entry_sel_text_fg_color;

                gfx_text_rect(&cpos, &cfmt, entry->text + off1, &sel);
                sel.p0.x -= ui_entry_sel_hpad;
                sel.p0.y -= ui_entry_sel_vpad;
                sel.p1.x += ui_entry_sel_hpad;
                sel.p1.y += ui_entry_sel_vpad;

                rc = gfx_set_color(res->gc, res->entry_sel_text_bg_color);
                if (rc != EOK)
                        goto error;

                rc = gfx_fill_rect(res->gc, &sel);
                if (rc != EOK)
                        goto error;

                rc = gfx_puttext(&cpos, &cfmt, entry->text + off1);
                if (rc != EOK) {
                        (void) gfx_set_clip_rect(res->gc, NULL);
                        goto error;
                }

                gfx_text_cont(&cpos, &cfmt, entry->text + off1, &cpos, &cfmt);

                entry->text[off2] = c;
        }

        /* Render trailing, non-selected text */
        cfmt.color = res->entry_fg_color;

        rc = gfx_puttext(&cpos, &cfmt, entry->text + off2);
        if (rc != EOK) {
                (void) gfx_set_clip_rect(res->gc, NULL);
                goto error;
        }

        if (entry->active) {
                /* Cursor */
                pos.x += ui_entry_lwidth(entry);

                rc = ui_entry_paint_cursor(entry, &pos);
                if (rc != EOK) {
                        (void) gfx_set_clip_rect(res->gc, NULL);
                        goto error;
                }
        }

        rc = gfx_set_clip_rect(res->gc, NULL);
        if (rc != EOK)
                goto error;

        rc = gfx_update(res->gc);
        if (rc != EOK)
                goto error;

        return EOK;
error:
        return rc;
}

/** Find position in text entry.
 *
 * @param entry Text entry
 * @param fpos Position for which we need to find text offset
 * @return Corresponding byte offset in entry text
 */
size_t ui_entry_find_pos(ui_entry_t *entry, gfx_coord2_t *fpos)
{
        ui_resource_t *res;
        ui_entry_geom_t geom;
        gfx_text_fmt_t fmt;

        res = ui_window_get_res(entry->window);

        ui_entry_get_geom(entry, &geom);

        gfx_text_fmt_init(&fmt);
        fmt.font = res->font;
        fmt.halign = gfx_halign_left;
        fmt.valign = gfx_valign_top;

        return gfx_text_find_pos(&geom.text_pos, &fmt, entry->text, fpos);
}

/** Destroy text entry control.
 *
 * @param arg Argument (ui_entry_t *)
 */
void ui_entry_ctl_destroy(void *arg)
{
        ui_entry_t *entry = (ui_entry_t *) arg;

        ui_entry_destroy(entry);
}

/** Paint text entry control.
 *
 * @param arg Argument (ui_entry_t *)
 * @return EOK on success or an error code
 */
errno_t ui_entry_ctl_paint(void *arg)
{
        ui_entry_t *entry = (ui_entry_t *) arg;

        return ui_entry_paint(entry);
}

/** Delete selected text.
 *
 * @param entry Text entry
 */
void ui_entry_delete_sel(ui_entry_t *entry)
{
        size_t off1;
        size_t off2;

        off1 = min(entry->sel_start, entry->pos);
        off2 = max(entry->sel_start, entry->pos);

        memmove(entry->text + off1, entry->text + off2,
            str_size(entry->text + off2) + 1);

        entry->pos = off1;
        entry->sel_start = off1;
        ui_entry_scroll_update(entry, false);
        ui_entry_paint(entry);
}

/** Insert string at cursor position.
 *
 * @param entry Text entry
 * @param str String
 * @return EOK on success, ENOMEM if out of memory
 */
errno_t ui_entry_insert_str(ui_entry_t *entry, const char *str)
{
        uint8_t tmp;
        char *ltext = NULL;
        char *newtext;
        char *oldtext;
        int rc;

        /* Do we have a selection? */
        if (entry->sel_start != entry->pos)
                ui_entry_delete_sel(entry);

        tmp = entry->text[entry->pos];
        entry->text[entry->pos] = '\0';
        ltext = str_dup(entry->text);
        if (ltext == NULL)
                return ENOMEM;

        entry->text[entry->pos] = tmp;

        rc = asprintf(&newtext, "%s%s%s", ltext, str, entry->text + entry->pos);
        if (rc < 0) {
                free(ltext);
                return ENOMEM;
        }

        oldtext = entry->text;
        entry->text = newtext;
        entry->pos += str_size(str);
        free(oldtext);
        free(ltext);

        entry->sel_start = entry->pos;
        ui_entry_scroll_update(entry, false);
        ui_entry_paint(entry);

        return EOK;
}

/** Delete character before cursor.
 *
 * @param entry Text entry
 */
void ui_entry_backspace(ui_entry_t *entry)
{
        size_t off;

        /* Do we have a selection? */
        if (entry->sel_start != entry->pos) {
                ui_entry_delete_sel(entry);
                return;
        }

        if (entry->pos == 0)
                return;

        /* Find offset where character before cursor starts */
        off = entry->pos;
        (void) str_decode_reverse(entry->text, &off,
            str_size(entry->text));

        memmove(entry->text + off, entry->text + entry->pos,
            str_size(entry->text + entry->pos) + 1);
        entry->pos = off;
        entry->sel_start = off;

        ui_entry_scroll_update(entry, false);
        ui_entry_paint(entry);
}

/** Delete character after cursor.
 *
 * @param entry Text entry
 */
void ui_entry_delete(ui_entry_t *entry)
{
        size_t off;

        /* Do we have a selection? */
        if (entry->sel_start != entry->pos) {
                ui_entry_delete_sel(entry);
                return;
        }

        /* Find offset where character after cursor ends */
        off = entry->pos;
        (void) str_decode(entry->text, &off,
            str_size(entry->text));

        memmove(entry->text + entry->pos, entry->text + off,
            str_size(entry->text + off) + 1);

        ui_entry_scroll_update(entry, false);
        ui_entry_paint(entry);
}

/** Copy selected text to clipboard.
 *
 * @param entry Text entry
 */
void ui_entry_copy(ui_entry_t *entry)
{
        unsigned off1;
        unsigned off2;
        char c;

        off1 = min(entry->pos, entry->sel_start);
        off2 = max(entry->pos, entry->sel_start);

        c = entry->text[off2];
        entry->text[off2] = '\0';

        (void) clipboard_put_str(entry->text + off1);

        entry->text[off2] = c;
}

/** Cut selected text to clipboard.
 *
 * @param entry Text entry
 */
void ui_entry_cut(ui_entry_t *entry)
{
        ui_entry_copy(entry);
        ui_entry_delete_sel(entry);
}

/** Paste text from clipboard.
 *
 * @param entry Text entry
 */
void ui_entry_paste(ui_entry_t *entry)
{
        char *str;
        errno_t rc;

        rc = clipboard_get_str(&str);
        if (rc != EOK)
                return;

        ui_entry_insert_str(entry, str);
        free(str);
}

/** Handle text entry key press without modifiers.
 *
 * @param entry Text entry
 * @param kbd_event Keyboard event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t ui_entry_key_press_unmod(ui_entry_t *entry, kbd_event_t *event)
{
        assert(event->type == KEY_PRESS);

        switch (event->key) {
        case KC_BACKSPACE:
                ui_entry_backspace(entry);
                break;

        case KC_DELETE:
                ui_entry_delete(entry);
                break;

        case KC_ESCAPE:
                ui_entry_deactivate(entry);
                break;

        case KC_HOME:
                ui_entry_seek_start(entry, false);
                break;

        case KC_END:
                ui_entry_seek_end(entry, false);
                break;

        case KC_LEFT:
                ui_entry_seek_prev_char(entry, false);
                break;

        case KC_RIGHT:
                ui_entry_seek_next_char(entry, false);
                break;

        default:
                break;
        }
        return ui_claimed;
}

/** Handle text entry key press with shift modifier.
 *
 * @param entry Text entry
 * @param kbd_event Keyboard event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t ui_entry_key_press_shift(ui_entry_t *entry, kbd_event_t *event)
{
        assert(event->type == KEY_PRESS);

        switch (event->key) {
        case KC_HOME:
                ui_entry_seek_start(entry, true);
                break;

        case KC_END:
                ui_entry_seek_end(entry, true);
                break;

        case KC_LEFT:
                ui_entry_seek_prev_char(entry, true);
                break;

        case KC_RIGHT:
                ui_entry_seek_next_char(entry, true);
                break;

        default:
                break;
        }

        return ui_claimed;
}

/** Handle text entry key press with control modifier.
 *
 * @param entry Text entry
 * @param kbd_event Keyboard event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t ui_entry_key_press_ctrl(ui_entry_t *entry, kbd_event_t *event)
{
        assert(event->type == KEY_PRESS);

        switch (event->key) {
        case KC_C:
                ui_entry_copy(entry);
                break;
        case KC_V:
                ui_entry_paste(entry);
                break;
        case KC_X:
                ui_entry_cut(entry);
                break;
        default:
                break;
        }

        return ui_claimed;
}

/** Handle text entry keyboard event.
 *
 * @param entry Text entry
 * @param kbd_event Keyboard event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t ui_entry_kbd_event(ui_entry_t *entry, kbd_event_t *event)
{
        char buf[STR_BOUNDS(1) + 1];
        size_t off;
        errno_t rc;

        if (!entry->active)
                return ui_unclaimed;

        /*
         * Need to keep track if any shift is held for the case
         * of selecting by shift-click. This could be simplified
         * if position events were decorated with modifier
         * state.
         */

        if (event->type == KEY_PRESS && event->key == KC_LSHIFT)
                entry->lshift_held = true;
        if (event->type == KEY_RELEASE && event->key == KC_LSHIFT)
                entry->lshift_held = false;
        if (event->type == KEY_PRESS && event->key == KC_RSHIFT)
                entry->rshift_held = true;
        if (event->type == KEY_RELEASE && event->key == KC_RSHIFT)
                entry->rshift_held = false;

        if (event->type == KEY_PRESS &&
            (event->mods & (KM_CTRL | KM_ALT)) == 0 && event->c >= ' ') {
                off = 0;
                rc = chr_encode(event->c, buf, &off, sizeof(buf));
                if (rc == EOK) {
                        buf[off] = '\0';
                        (void) ui_entry_insert_str(entry, buf);
                }
        }

        if (event->type == KEY_PRESS &&
            (event->mods & (KM_CTRL | KM_ALT | KM_SHIFT)) == 0)
                return ui_entry_key_press_unmod(entry, event);

        if (event->type == KEY_PRESS &&
            (event->mods & KM_SHIFT) != 0 &&
            (event->mods & (KM_CTRL | KM_ALT)) == 0)
                return ui_entry_key_press_shift(entry, event);

        if (event->type == KEY_PRESS &&
            (event->mods & KM_CTRL) != 0 &&
            (event->mods & (KM_ALT | KM_SHIFT)) == 0)
                return ui_entry_key_press_ctrl(entry, event);

        return ui_claimed;
}

/** Handle text entry position event.
 *
 * @param entry Text entry
 * @param pos_event Position event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t ui_entry_pos_event(ui_entry_t *entry, pos_event_t *event)
{
        gfx_coord2_t pos;

        if (entry->read_only)
                return ui_unclaimed;

        if (event->type == POS_UPDATE) {
                pos.x = event->hpos;
                pos.y = event->vpos;

                /* Change cursor shape when pointer is entering/leaving */
                if (gfx_pix_inside_rect(&pos, &entry->rect)) {
                        if (!entry->pointer_inside) {
                                ui_window_set_ctl_cursor(entry->window,
                                    ui_curs_ibeam);
                                entry->pointer_inside = true;
                        }
                } else {
                        if (entry->pointer_inside) {
                                ui_window_set_ctl_cursor(entry->window,
                                    ui_curs_arrow);
                                entry->pointer_inside = false;
                        }
                }

                if (entry->held) {
                        /*
                         * Selecting using mouse drag: Change pos,
                         * keep sel_start
                         */
                        entry->pos = ui_entry_find_pos(entry, &pos);
                        ui_entry_paint(entry);
                }
        }

        if (event->type == POS_PRESS) {
                pos.x = event->hpos;
                pos.y = event->vpos;

                if (gfx_pix_inside_rect(&pos, &entry->rect)) {
                        /* Clicked inside - activate, set position */
                        entry->held = true;
                        entry->pos = ui_entry_find_pos(entry, &pos);

                        /* Clear selection if no shift key is held */
                        if (!entry->lshift_held && !entry->rshift_held)
                                entry->sel_start = entry->pos;

                        if (entry->active)
                                ui_entry_paint(entry);
                        else
                                ui_entry_activate(entry);

                        return ui_claimed;
                } else {
                        /* Clicked outside - deactivate */
                        ui_entry_deactivate(entry);
                }
        }

        if (event->type == POS_RELEASE) {
                entry->held = false;
        }

        return ui_unclaimed;
}

/** Handle text entry control keyboard event.
 *
 * @param arg Argument (ui_entry_t *)
 * @param kbd_event Keyboard event
 * @return @c ui_claimed iff the event is claimed
 */
static ui_evclaim_t ui_entry_ctl_kbd_event(void *arg, kbd_event_t *event)
{
        ui_entry_t *entry = (ui_entry_t *) arg;

        return ui_entry_kbd_event(entry, event);
}

/** Handle text entry control position event.
 *
 * @param arg Argument (ui_entry_t *)
 * @param pos_event Position event
 * @return @c ui_claimed iff the event is claimed
 */
static ui_evclaim_t ui_entry_ctl_pos_event(void *arg, pos_event_t *event)
{
        ui_entry_t *entry = (ui_entry_t *) arg;

        return ui_entry_pos_event(entry, event);
}

/** Get text entry geometry.
 *
 * @param entry Text entry
 * @param geom Structure to fill in with computed geometry
 */
void ui_entry_get_geom(ui_entry_t *entry, ui_entry_geom_t *geom)
{
        gfx_coord_t hpad;
        gfx_coord_t vpad;
        ui_resource_t *res;

        res = ui_window_get_res(entry->window);

        if (res->textmode) {
                hpad = ui_entry_hpad_text;
                vpad = ui_entry_vpad_text;
        } else {
                hpad = ui_entry_hpad;
                vpad = ui_entry_vpad;
        }

        if (res->textmode == false) {
                ui_paint_get_inset_frame_inside(res, &entry->rect,
                    &geom->interior_rect);
        } else {
                geom->interior_rect = entry->rect;
        }

        geom->text_rect.p0.x = geom->interior_rect.p0.x + hpad;
        geom->text_rect.p0.y = geom->interior_rect.p0.y + vpad;
        geom->text_rect.p1.x = geom->interior_rect.p1.x - hpad;
        geom->text_rect.p1.y = geom->interior_rect.p1.y - vpad;

        geom->text_pos.x = geom->interior_rect.p0.x + hpad +
            entry->scroll_pos;
        geom->text_pos.y = geom->interior_rect.p0.y + vpad;

        switch (entry->halign) {
        case gfx_halign_left:
        case gfx_halign_justify:
                geom->anchor_x = geom->text_rect.p0.x;
                break;
        case gfx_halign_center:
                geom->anchor_x = (geom->text_rect.p0.x +
                    geom->text_rect.p1.x) / 2;
                break;
        case gfx_halign_right:
                geom->anchor_x = geom->text_rect.p1.x;
                break;
        }
}

/** Activate text entry.
 *
 * @param entry Text entry
 */
void ui_entry_activate(ui_entry_t *entry)
{
        ui_resource_t *res;

        res = ui_window_get_res(entry->window);

        if (entry->active)
                return;

        entry->active = true;
        (void) ui_entry_paint(entry);

        if (res->textmode)
                gfx_cursor_set_visible(res->gc, true);
}

/** Move text cursor to the beginning of text.
 *
 * @param entry Text entry
 * @param shift @c true iff shift key is pressed
 */
void ui_entry_seek_start(ui_entry_t *entry, bool shift)
{
        entry->pos = 0;

        if (!shift)
                entry->sel_start = entry->pos;

        ui_entry_scroll_update(entry, false);
        (void) ui_entry_paint(entry);
}

/** Move text cursor to the end of text.
 *
 * @param entry Text entry
 * @param shift @c true iff shift key is pressed
 */
void ui_entry_seek_end(ui_entry_t *entry, bool shift)
{
        entry->pos = str_size(entry->text);

        if (!shift)
                entry->sel_start = entry->pos;

        ui_entry_scroll_update(entry, false);
        (void) ui_entry_paint(entry);
}

/** Move text cursor one character backward.
 *
 * @param entry Text entry
 * @param shift @c true iff shift key is pressed
 */
void ui_entry_seek_prev_char(ui_entry_t *entry, bool shift)
{
        size_t off;

        off = entry->pos;
        (void) str_decode_reverse(entry->text, &off,
            str_size(entry->text));
        entry->pos = off;

        if (!shift)
                entry->sel_start = entry->pos;

        ui_entry_scroll_update(entry, false);
        (void) ui_entry_paint(entry);
}

/** Move text cursor one character forward.
 *
 * @param entry Text entry
 * @param shift @c true iff shift key is pressed
 */
void ui_entry_seek_next_char(ui_entry_t *entry, bool shift)
{
        size_t off;

        off = entry->pos;
        (void) str_decode(entry->text, &off,
            str_size(entry->text));
        entry->pos = off;

        if (!shift)
                entry->sel_start = entry->pos;

        ui_entry_scroll_update(entry, false);
        (void) ui_entry_paint(entry);
}

/** Deactivate text entry.
 *
 * @param entry Text entry
 */
void ui_entry_deactivate(ui_entry_t *entry)
{
        ui_resource_t *res;

        res = ui_window_get_res(entry->window);

        if (!entry->active)
                return;

        entry->active = false;
        entry->sel_start = entry->pos;
        (void) ui_entry_paint(entry);

        if (res->textmode)
                gfx_cursor_set_visible(res->gc, false);
}

/** Update text entry scroll position.
 *
 * @param entry Text entry
 * @param realign @c true iff we should left-align short text.
 *                This should be only used when changing text alignment,
 *                because left-aligned text entries should not realign
 *                the text to the left side under normal circumstances.
 */
void ui_entry_scroll_update(ui_entry_t *entry, bool realign)
{
        ui_entry_geom_t geom;
        gfx_coord_t x;
        gfx_coord_t width;
        gfx_coord2_t tpos;
        gfx_coord2_t anchor;
        gfx_text_fmt_t fmt;
        ui_resource_t *res;

        res = ui_window_get_res(entry->window);

        ui_entry_get_geom(entry, &geom);

        /* Compute position where cursor is currently displayed at */
        x = geom.text_pos.x + ui_entry_lwidth(entry);

        /* Is cursor off to the left? */
        if (x < geom.text_rect.p0.x) {
                /*
                 * Scroll to make cursor visible and put some space between it
                 * and the left edge of the text rectangle.
                 */
                entry->scroll_pos += geom.text_rect.p0.x - x +
                    ui_entry_left_scroll_margin;

                /*
                 * We don't want to scroll further than what's needed
                 * to reveal the beginning of the text.
                 */
                if (entry->scroll_pos > 0)
                        entry->scroll_pos = 0;
        }

        /*
         * Is cursor off to the right? Note that the width of the cursor
         * is deliberately not taken into account (i.e. we only care
         * about the left edge of the cursor).
         */
        if (x > geom.text_rect.p1.x)
                entry->scroll_pos -= x - geom.text_rect.p1.x;

        width = gfx_text_width(res->font, entry->text);

        if (width < geom.text_rect.p1.x - geom.text_rect.p0.x &&
            (realign || entry->halign != gfx_halign_left)) {
                /* Text fits inside entry, so we need to align it */
                anchor.x = geom.anchor_x;
                anchor.y = 0;
                gfx_text_fmt_init(&fmt);
                fmt.font = res->font;
                fmt.halign = entry->halign;
                gfx_text_start_pos(&anchor, &fmt, entry->text, &tpos);
                entry->scroll_pos = tpos.x - geom.text_rect.p0.x;
        } else if (geom.text_pos.x + width < geom.text_rect.p1.x &&
            entry->halign != gfx_halign_left) {
                /* Text is long, unused space on the right */
                entry->scroll_pos += geom.text_rect.p1.x -
                    geom.text_pos.x - width;
        }
}

/** @}
 */