source: mainline/uspace/lib/gfxfont/src/text.c@ 8bf9058

/*
 * Copyright (c) 2020 Jiri Svoboda
 * 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.
 */

/** @addtogroup libgfxfont
 * @{
 */
/**
 * @file Text rendering
 */

#include <errno.h>
#include <gfx/font.h>
#include <gfx/glyph.h>
#include <gfx/text.h>
#include <mem.h>

/** Initialize text formatting structure.
 *
 * Text formatting structure must always be initialized using this function
 * first.
 *
 * @param fmt Text formatting structure
 */
void gfx_text_fmt_init(gfx_text_fmt_t *fmt)
{
        memset(fmt, 0, sizeof(gfx_text_fmt_t));
}

/** Compute text width.
 *
 * @param font Font
 * @param str String
 * @return Text width
 */
gfx_coord_t gfx_text_width(gfx_font_t *font, const char *str)
{
        gfx_glyph_metrics_t gmetrics;
        size_t stradv;
        const char *cp;
        gfx_glyph_t *glyph;
        gfx_coord_t width;
        errno_t rc;

        width = 0;
        cp = str;
        while (*cp != '\0') {
                rc = gfx_font_search_glyph(font, cp, &glyph, &stradv);
                if (rc != EOK) {
                        ++cp;
                        continue;
                }

                gfx_glyph_get_metrics(glyph, &gmetrics);

                cp += stradv;
                width += gmetrics.advance;
        }

        return width;
}

/** Render text.
 *
 * @param font Font
 * @param pos Anchor position
 * @param fmt Text formatting
 * @param str String
 * @return EOK on success or an error code
 */
errno_t gfx_puttext(gfx_font_t *font, gfx_coord2_t *pos,
    gfx_text_fmt_t *fmt, const char *str)
{
        gfx_font_metrics_t fmetrics;
        gfx_glyph_metrics_t gmetrics;
        size_t stradv;
        const char *cp;
        gfx_glyph_t *glyph;
        gfx_coord2_t cpos;
        gfx_coord_t width;
        errno_t rc;

        cpos = *pos;

        /* Adjust position for horizontal alignment */
        if (fmt->halign != gfx_halign_left) {
                width = gfx_text_width(font, str);
                switch (fmt->halign) {
                case gfx_halign_center:
                        cpos.x -= width / 2;
                        break;
                case gfx_halign_right:
                        cpos.x -= width;
                        break;
                default:
                        break;
                }
        }

        /* Adjust position for vertical alignment */
        gfx_font_get_metrics(font, &fmetrics);

        if (fmt->valign != gfx_valign_baseline) {
                switch (fmt->valign) {
                case gfx_valign_top:
                        cpos.y += fmetrics.ascent;
                        break;
                case gfx_valign_center:
                        cpos.y += fmetrics.ascent / 2;
                        break;
                case gfx_valign_bottom:
                        cpos.y -= fmetrics.descent;
                        break;
                default:
                        break;
                }
        }

        cp = str;
        while (*cp != '\0') {
                rc = gfx_font_search_glyph(font, cp, &glyph, &stradv);
                if (rc != EOK) {
                        ++cp;
                        continue;
                }

                gfx_glyph_get_metrics(glyph, &gmetrics);

                rc = gfx_glyph_render(glyph, &cpos);
                if (rc != EOK)
                        return rc;

                cp += stradv;
                cpos.x += gmetrics.advance;
        }

        return EOK;
}

/** @}
 */