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Diffstat (limited to 'trunk/pango/pangoft2-render.c')
| -rw-r--r-- | trunk/pango/pangoft2-render.c | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/trunk/pango/pangoft2-render.c b/trunk/pango/pangoft2-render.c new file mode 100644 index 00000000..ef052efa --- /dev/null +++ b/trunk/pango/pangoft2-render.c @@ -0,0 +1,710 @@ +/* Pango + * pangoft2-render.c: Rendering routines to FT_Bitmap objects + * + * Copyright (C) 2004 Red Hat Software + * Copyright (C) 2000 Tor Lillqvist + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include <config.h> +#include <math.h> + +#include "pangoft2-private.h" + +/* for compatibility with older freetype versions */ +#ifndef FT_LOAD_TARGET_MONO +#define FT_LOAD_TARGET_MONO FT_LOAD_MONOCHROME +#endif + +typedef struct _PangoFT2RendererClass PangoFT2RendererClass; + +#define PANGO_FT2_RENDERER_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), PANGO_TYPE_FT2_RENDERER, PangoFT2RendererClass)) +#define PANGO_IS_FT2_RENDERER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), PANGO_TYPE_FT2_RENDERER)) +#define PANGO_FT2_RENDERER_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), PANGO_TYPE_FT2_RENDERER, PangoFT2RendererClass)) + +struct _PangoFT2Renderer +{ + PangoRenderer parent_instance; + + FT_Bitmap *bitmap; +}; + +struct _PangoFT2RendererClass +{ + PangoRendererClass parent_class; +}; + +static void pango_ft2_renderer_draw_glyph (PangoRenderer *renderer, + PangoFont *font, + PangoGlyph glyph, + double x, + double y); +static void pango_ft2_renderer_draw_trapezoid (PangoRenderer *renderer, + PangoRenderPart part, + double y1, + double x11, + double x21, + double y2, + double x12, + double x22); + +G_DEFINE_TYPE (PangoFT2Renderer, pango_ft2_renderer, PANGO_TYPE_RENDERER) + +static void +pango_ft2_renderer_init (PangoFT2Renderer *renderer) +{ +} + +static void +pango_ft2_renderer_class_init (PangoFT2RendererClass *klass) +{ + PangoRendererClass *renderer_class = PANGO_RENDERER_CLASS (klass); + + renderer_class->draw_glyph = pango_ft2_renderer_draw_glyph; + renderer_class->draw_trapezoid = pango_ft2_renderer_draw_trapezoid; +} + +static void +pango_ft2_renderer_set_bitmap (PangoFT2Renderer *renderer, + FT_Bitmap *bitmap) +{ + renderer->bitmap = bitmap; +} + +typedef struct +{ + FT_Bitmap bitmap; + int bitmap_left; + int bitmap_top; +} PangoFT2RenderedGlyph; + +static void +pango_ft2_free_rendered_glyph (PangoFT2RenderedGlyph *rendered) +{ + g_free (rendered->bitmap.buffer); + g_slice_free (PangoFT2RenderedGlyph, rendered); +} + +static PangoFT2RenderedGlyph * +pango_ft2_font_render_box_glyph (int width, + int height, + int top) +{ + PangoFT2RenderedGlyph *box; + int i, j, offset1, offset2, line_width; + + line_width = MAX ((height + 43) / 44, 1); + if (width < 1 || height < 1) + line_width = 0; + + box = g_slice_new (PangoFT2RenderedGlyph); + + box->bitmap_left = 0; + box->bitmap_top = top; + + box->bitmap.pixel_mode = ft_pixel_mode_grays; + + box->bitmap.width = width; + box->bitmap.rows = height; + box->bitmap.pitch = height; + + box->bitmap.buffer = g_malloc0 (box->bitmap.rows * box->bitmap.pitch); + + /* draw the box */ + for (j = 0; j < line_width; j++) + { + offset1 = box->bitmap.pitch * (MIN (1 + j, height - 1)); + offset2 = box->bitmap.pitch * (MAX (box->bitmap.rows - 2 - j, 0)); + for (i = 1; + i < box->bitmap.width - 1; + i++) + { + box->bitmap.buffer[offset1 + i] = 0xff; + box->bitmap.buffer[offset2 + i] = 0xff; + } + } + for (j = 0; j < line_width; j++) + { + offset1 = MIN (1 + j, width - 1); + offset2 = MAX (box->bitmap.width - 2 - j, 0); + for (i = box->bitmap.pitch; + i < (box->bitmap.rows - 1) * box->bitmap.pitch; + i += box->bitmap.pitch) + { + box->bitmap.buffer[offset1 + i] = 0xff; + box->bitmap.buffer[offset2 + i] = 0xff; + } + } + + return box; +} + +static PangoFT2RenderedGlyph * +pango_ft2_font_render_glyph (PangoFont *font, + int glyph_index) +{ + FT_Face face; + + if (glyph_index & PANGO_GLYPH_UNKNOWN_FLAG) + { + PangoFT2RenderedGlyph *box; + PangoFontMetrics *metrics; + + if (!font) + goto generic_box; + + metrics = pango_font_get_metrics (font, NULL); + if (!metrics) + goto generic_box; + + box = pango_ft2_font_render_box_glyph (PANGO_PIXELS (metrics->approximate_char_width), + PANGO_PIXELS (metrics->ascent + metrics->descent), + PANGO_PIXELS (metrics->ascent)); + pango_font_metrics_unref (metrics); + + return box; + } + + face = pango_ft2_font_get_face (font); + + if (face) + { + PangoFT2RenderedGlyph *rendered; + PangoFT2Font *ft2font = (PangoFT2Font *) font; + + rendered = g_slice_new (PangoFT2RenderedGlyph); + + /* Draw glyph */ + FT_Load_Glyph (face, glyph_index, ft2font->load_flags); + FT_Render_Glyph (face->glyph, + (ft2font->load_flags & FT_LOAD_TARGET_MONO ? + ft_render_mode_mono : ft_render_mode_normal)); + + rendered->bitmap = face->glyph->bitmap; + rendered->bitmap.buffer = g_memdup (face->glyph->bitmap.buffer, + face->glyph->bitmap.rows * face->glyph->bitmap.pitch); + rendered->bitmap_left = face->glyph->bitmap_left; + rendered->bitmap_top = face->glyph->bitmap_top; + + return rendered; + } + else + { +generic_box: + return pango_ft2_font_render_box_glyph (PANGO_UNKNOWN_GLYPH_WIDTH, + PANGO_UNKNOWN_GLYPH_HEIGHT, + PANGO_UNKNOWN_GLYPH_HEIGHT); + } +} + +static void +pango_ft2_renderer_draw_glyph (PangoRenderer *renderer, + PangoFont *font, + PangoGlyph glyph, + double x, + double y) +{ + FT_Bitmap *bitmap = PANGO_FT2_RENDERER (renderer)->bitmap; + PangoFT2RenderedGlyph *rendered_glyph; + gboolean add_glyph_to_cache; + guchar *src, *dest; + + int x_start, x_limit; + int y_start, y_limit; + int ixoff = floor (x + 0.5); + int iyoff = floor (y + 0.5); + int ix, iy; + + if (glyph & PANGO_GLYPH_UNKNOWN_FLAG) + { + glyph = pango_ft2_get_unknown_glyph (font); + if (glyph == PANGO_GLYPH_EMPTY) + { + /* No unknown glyph found for the font, draw a box */ + + /* Since we only draw an empty box for FT2 renderer, + * we unify the rendered bitmaps in the cache. + */ + glyph = PANGO_GLYPH_UNKNOWN_FLAG; + } + } + + rendered_glyph = _pango_ft2_font_get_cache_glyph_data (font, glyph); + add_glyph_to_cache = FALSE; + if (rendered_glyph == NULL) + { + rendered_glyph = pango_ft2_font_render_glyph (font, glyph); + add_glyph_to_cache = TRUE; + } + + x_start = MAX (0, - (ixoff + rendered_glyph->bitmap_left)); + x_limit = MIN (rendered_glyph->bitmap.width, + bitmap->width - (ixoff + rendered_glyph->bitmap_left)); + + y_start = MAX (0, - (iyoff - rendered_glyph->bitmap_top)); + y_limit = MIN (rendered_glyph->bitmap.rows, + bitmap->rows - (iyoff - rendered_glyph->bitmap_top)); + + src = rendered_glyph->bitmap.buffer + + y_start * rendered_glyph->bitmap.pitch; + + dest = bitmap->buffer + + (y_start + iyoff - rendered_glyph->bitmap_top) * bitmap->pitch + + x_start + ixoff + rendered_glyph->bitmap_left; + + switch (rendered_glyph->bitmap.pixel_mode) + { + case ft_pixel_mode_grays: + src += x_start; + for (iy = y_start; iy < y_limit; iy++) + { + guchar *s = src; + guchar *d = dest; + + for (ix = x_start; ix < x_limit; ix++) + { + switch (*s) + { + case 0: + break; + case 0xff: + *d = 0xff; + default: + *d = MIN ((gushort) *d + (gushort) *s, 0xff); + break; + } + + s++; + d++; + } + + dest += bitmap->pitch; + src += rendered_glyph->bitmap.pitch; + } + break; + + case ft_pixel_mode_mono: + src += x_start / 8; + for (iy = y_start; iy < y_limit; iy++) + { + guchar *s = src; + guchar *d = dest; + + for (ix = x_start; ix < x_limit; ix++) + { + if ((*s) & (1 << (7 - (ix % 8)))) + *d |= 0xff; + + if ((ix % 8) == 7) + s++; + d++; + } + + dest += bitmap->pitch; + src += rendered_glyph->bitmap.pitch; + } + break; + + default: + g_warning ("pango_ft2_render: " + "Unrecognized glyph bitmap pixel mode %d\n", + rendered_glyph->bitmap.pixel_mode); + break; + } + + if (add_glyph_to_cache) + { + _pango_ft2_font_set_glyph_cache_destroy (font, + (GDestroyNotify) pango_ft2_free_rendered_glyph); + _pango_ft2_font_set_cache_glyph_data (font, + glyph, rendered_glyph); + } +} + +typedef struct { + double y; + double x1; + double x2; +} Position; + +static void +draw_simple_trap (PangoRenderer *renderer, + Position *t, + Position *b) +{ + FT_Bitmap *bitmap = PANGO_FT2_RENDERER (renderer)->bitmap; + int iy = floor (t->y); + int x1, x2, x; + double dy = b->y - t->y; + guchar *dest; + + if (iy < 0 || iy >= bitmap->rows) + return; + dest = bitmap->buffer + iy * bitmap->pitch; + + if (t->x1 < b->x1) + x1 = floor (t->x1); + else + x1 = floor (b->x1); + + if (t->x2 > b->x2) + x2 = ceil (t->x2); + else + x2 = ceil (b->x2); + + x1 = CLAMP (x1, 0, bitmap->width); + x2 = CLAMP (x2, 0, bitmap->width); + + for (x = x1; x < x2; x++) + { + double top_left = MAX (t->x1, x); + double top_right = MIN (t->x2, x + 1); + double bottom_left = MAX (b->x1, x); + double bottom_right = MIN (b->x2, x + 1); + double c = 0.5 * dy * ((top_right - top_left) + (bottom_right - bottom_left)); + + /* When converting to [0,255], we round up. This is intended + * to prevent the problem of pixels that get divided into + * multiple slices not being fully black. + */ + int ic = c * 256; + + dest[x] = MIN (dest[x] + ic, 255); + } +} + +static void +interpolate_position (Position *result, + Position *top, + Position *bottom, + double val, + double val1, + double val2) +{ + result->y = (top->y * (val2 - val) + bottom->y * (val - val1)) / (val2 - val1); + result->x1 = (top->x1 * (val2 - val) + bottom->x1 * (val - val1)) / (val2 - val1); + result->x2 = (top->x2 * (val2 - val) + bottom->x2 * (val - val1)) / (val2 - val1); +} + +/* This draws a trapezoid with the parallel sides aligned with + * the X axis. We do this by subdividing the trapezoid vertically + * into thin slices (themselves trapezoids) where two edge sides are each + * contained within a single pixel and then rasterizing each + * slice. There are frequently multiple slices within a single + * line so we have to accumulate to get the final result. + */ +static void +pango_ft2_renderer_draw_trapezoid (PangoRenderer *renderer, + PangoRenderPart part, + double y1, + double x11, + double x21, + double y2, + double x12, + double x22) +{ + Position pos; + Position t; + Position b; + gboolean done = FALSE; + + if (y1 == y2) + return; + + pos.y = t.y = y1; + pos.x1 = t.x1 = x11; + pos.x2 = t.x2 = x21; + b.y = y2; + b.x1 = x12; + b.x2 = x22; + + while (!done) + { + Position pos_next; + double y_next, x1_next, x2_next; + double ix1, ix2; + + /* The algorithm here is written to emphasize simplicity and + * numerical stability as opposed to speed. + * + * While the end result is slicing up the polygon vertically, + * conceptually we aren't walking in the X direction, rather we + * are walking along the edges. When we compute crossing of + * horizontal pixel boundaries, we use the X coordinate as the + * interpolating variable, when we compute crossing for vertical + * pixel boundaries, we use the Y coordinate. + * + * This allows us to handle almost exactly horizontal edges without + * running into difficulties. (Almost exactly horizontal edges + * come up frequently due to inexactness in computing, say, + * a 90 degree rotation transformation) + */ + + pos_next = b; + done = TRUE; + + /* Check for crossing vertical pixel boundaries */ + y_next = floor (pos.y) + 1; + if (y_next < pos_next.y) + { + interpolate_position (&pos_next, &t, &b, + y_next, t.y, b.y); + pos_next.y = y_next; + done = FALSE; + } + + /* Check left side for crossing horizontal pixel boundaries */ + ix1 = floor (pos.x1); + + if (b.x1 < t.x1) + { + if (ix1 == pos.x1) + x1_next = ix1 - 1; + else + x1_next = ix1; + + if (x1_next > pos_next.x1) + { + interpolate_position (&pos_next, &t, &b, + x1_next, t.x1, b.x1); + pos_next.x1 = x1_next; + done = FALSE; + } + } + else if (b.x1 > t.x1) + { + x1_next = ix1 + 1; + + if (x1_next < pos_next.x1) + { + interpolate_position (&pos_next, &t, &b, + x1_next, t.x1, b.x1); + pos_next.x1 = x1_next; + done = FALSE; + } + } + + /* Check right side for crossing horizontal pixel boundaries */ + ix2 = floor (pos.x2); + + if (b.x2 < t.x2) + { + if (ix2 == pos.x2) + x2_next = ix2 - 1; + else + x2_next = ix2; + + if (x2_next > pos_next.x2) + { + interpolate_position (&pos_next, &t, &b, + x2_next, t.x2, b.x2); + pos_next.x2 = x2_next; + done = FALSE; + } + } + else if (x22 > x21) + { + x2_next = ix2 + 1; + + if (x2_next < pos_next.x2) + { + interpolate_position (&pos_next, &t, &b, + x2_next, t.x2, b.x2); + pos_next.x2 = x2_next; + done = FALSE; + } + } + + draw_simple_trap (renderer, &pos, &pos_next); + pos = pos_next; + } +} + +/** + * pango_ft2_render_layout_subpixel: + * @bitmap: a <type>FT_Bitmap</type> to render the layout onto + * @layout: a #PangoLayout + * @x: the X position of the left of the layout (in Pango units) + * @y: the Y position of the top of the layout (in Pango units) + * + * Render a #PangoLayout onto a FreeType2 bitmap, with he + * location specified in fixed-point Pango units rather than + * pixels. (Using this will avoid extra inaccuracies from + * rounding to integer pixels multiple times, even if the + * final glyph positions are integers.) + * + * Since: 1.6 + */ +void +pango_ft2_render_layout_subpixel (FT_Bitmap *bitmap, + PangoLayout *layout, + int x, + int y) +{ + PangoContext *context; + PangoFontMap *fontmap; + PangoRenderer *renderer; + + g_return_if_fail (bitmap != NULL); + g_return_if_fail (PANGO_IS_LAYOUT (layout)); + + context = pango_layout_get_context (layout); + fontmap = pango_context_get_font_map (context); + renderer = _pango_ft2_font_map_get_renderer (PANGO_FT2_FONT_MAP (fontmap)); + + pango_ft2_renderer_set_bitmap (PANGO_FT2_RENDERER (renderer), bitmap); + + pango_renderer_draw_layout (renderer, layout, x, y); +} + +/** + * pango_ft2_render_layout: + * @bitmap: a <type>FT_Bitmap</type> to render the layout onto + * @layout: a #PangoLayout + * @x: the X position of the left of the layout (in pixels) + * @y: the Y position of the top of the layout (in pixels) + * + * Render a #PangoLayout onto a FreeType2 bitmap + */ +void +pango_ft2_render_layout (FT_Bitmap *bitmap, + PangoLayout *layout, + int x, + int y) +{ + pango_ft2_render_layout_subpixel (bitmap, layout, x * PANGO_SCALE, y * PANGO_SCALE); +} + +/** + * pango_ft2_render_layout_line_subpixel: + * @bitmap: a <type>FT_Bitmap</type> to render the line onto + * @line: a #PangoLayoutLine + * @x: the x position of start of string (in Pango units) + * @y: the y position of baseline (in Pango units) + * + * Render a #PangoLayoutLine onto a FreeType2 bitmap, with he + * location specified in fixed-point Pango units rather than + * pixels. (Using this will avoid extra inaccuracies from + * rounding to integer pixels multiple times, even if the + * final glyph positions are integers.) + * + * Since: 1.6 + */ +void +pango_ft2_render_layout_line_subpixel (FT_Bitmap *bitmap, + PangoLayoutLine *line, + int x, + int y) +{ + PangoContext *context; + PangoFontMap *fontmap; + PangoRenderer *renderer; + + g_return_if_fail (bitmap != NULL); + g_return_if_fail (line != NULL); + + context = pango_layout_get_context (line->layout); + fontmap = pango_context_get_font_map (context); + renderer = _pango_ft2_font_map_get_renderer (PANGO_FT2_FONT_MAP (fontmap)); + + pango_ft2_renderer_set_bitmap (PANGO_FT2_RENDERER (renderer), bitmap); + + pango_renderer_draw_layout_line (renderer, line, x, y); +} + +/** + * pango_ft2_render_layout_line: + * @bitmap: a <type>FT_Bitmap</type> to render the line onto + * @line: a #PangoLayoutLine + * @x: the x position of start of string (in pixels) + * @y: the y position of baseline (in pixels) + * + * Render a #PangoLayoutLine onto a FreeType2 bitmap + */ +void +pango_ft2_render_layout_line (FT_Bitmap *bitmap, + PangoLayoutLine *line, + int x, + int y) +{ + pango_ft2_render_layout_line_subpixel (bitmap, line, x * PANGO_SCALE, y * PANGO_SCALE); +} + +/** + * pango_ft2_render_transformed: + * @bitmap: the FreeType2 bitmap onto which to draw the string + * @font: the font in which to draw the string + * @matrix: a #PangoMatrix, or %NULL to use an identity transformation + * @glyphs: the glyph string to draw + * @x: the x position of the start of the string (in Pango + * units in user space coordinates) + * @y: the y position of the baseline (in Pango units + * in user space coordinates) + * + * Renders a #PangoGlyphString onto a FreeType2 bitmap, possibly + * transforming the layed-out coordinates through a transformation + * matrix. Note that the transformation matrix for @font is not + * changed, so to produce correct rendering results, the @font + * must have been loaded using a #PangoContext with an identical + * transformation matrix to that passed in to this function. + * + * Since: 1.6 + **/ +void +pango_ft2_render_transformed (FT_Bitmap *bitmap, + const PangoMatrix *matrix, + PangoFont *font, + PangoGlyphString *glyphs, + int x, + int y) +{ + PangoFontMap *fontmap; + PangoRenderer *renderer; + + g_return_if_fail (bitmap != NULL); + g_return_if_fail (glyphs != NULL); + g_return_if_fail (PANGO_FT2_IS_FONT (font)); + + fontmap = PANGO_FC_FONT (font)->fontmap; + renderer = _pango_ft2_font_map_get_renderer (PANGO_FT2_FONT_MAP (fontmap)); + + pango_ft2_renderer_set_bitmap (PANGO_FT2_RENDERER (renderer), bitmap); + pango_renderer_set_matrix (renderer, matrix); + + pango_renderer_draw_glyphs (renderer, font, glyphs, x, y); +} + +/** + * pango_ft2_render: + * @bitmap: the FreeType2 bitmap onto which to draw the string + * @font: the font in which to draw the string + * @glyphs: the glyph string to draw + * @x: the x position of the start of the string (in pixels) + * @y: the y position of the baseline (in pixels) + * + * Renders a #PangoGlyphString onto a FreeType2 bitmap. + **/ +void +pango_ft2_render (FT_Bitmap *bitmap, + PangoFont *font, + PangoGlyphString *glyphs, + int x, + int y) +{ + pango_ft2_render_transformed (bitmap, NULL, font, glyphs, x * PANGO_SCALE, y * PANGO_SCALE); +} + |