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authorGrigori Goronzy <greg@hein>2009-07-07 20:25:55 +0200
committerGrigori Goronzy <greg@blackbox>2009-07-07 23:07:50 +0200
commitf54a0cf94853d8372225bb0b45d6bd2b8e4e6fde (patch)
tree9c0e3b14e8ecf6e8cc1fe3f2107aad94d134cdd4
parent5a2b270b218a429763f0a032386705f55bca0a92 (diff)
downloadlibass-f54a0cf94853d8372225bb0b45d6bd2b8e4e6fde.tar.bz2
libass-f54a0cf94853d8372225bb0b45d6bd2b8e4e6fde.tar.xz
Support for underline and strikethrough
Add support for the underline (\u) and strikethrough/strikeout (\s) properties. This is a bit tricky, since FreeType doesn't offer any method of adding the lines, so you have to draw them yourself. libass uses various information from TrueType tables to get position and size of the lines, does a few simple consistency checks (some fonts might be broken) and if everything is alright, adds new contours for the lines. Sometimes, rendering errors can occur: - Currently, kerning isn't taken into account, which means the lines can overlap a little, leading to small optical glitches. - Some (broken) fonts use the wrong winding direction. In this case, the FreeType stroker will only consider the added lines to be "outside" and only stroke the line instead of the whole glyph.
-rw-r--r--libass/ass_cache_template.c1
-rw-r--r--libass/ass_drawing.c2
-rw-r--r--libass/ass_font.c86
-rw-r--r--libass/ass_font.h8
-rw-r--r--libass/ass_render.c20
5 files changed, 111 insertions, 6 deletions
diff --git a/libass/ass_cache_template.c b/libass/ass_cache_template.c
index bccb6db..eae9807 100644
--- a/libass/ass_cache_template.c
+++ b/libass/ass_cache_template.c
@@ -93,6 +93,7 @@ START(glyph, glyph_hash_key_s)
FTVECTOR(advance) // subpixel shift vector
FTVECTOR(outline) // border width, 16.16
GENERIC(unsigned, drawing_hash) // hashcode of a drawing
+ GENERIC(unsigned, flags) // glyph decoration flags
END(glyph_hash_key_t)
// Cache for composited bitmaps
diff --git a/libass/ass_drawing.c b/libass/ass_drawing.c
index 30d742f..09cf2d0 100644
--- a/libass/ass_drawing.c
+++ b/libass/ass_drawing.c
@@ -40,7 +40,7 @@ static void drawing_make_glyph(ass_drawing_t *drawing, void *fontconfig_priv,
// This is hacky...
glyph = (FT_OutlineGlyph) ass_font_get_glyph(fontconfig_priv, font,
- (uint32_t) ' ', hint);
+ (uint32_t) ' ', hint, 0);
FT_Outline_Done(drawing->ftlibrary, &glyph->outline);
FT_Outline_New(drawing->ftlibrary, GLYPH_INITIAL_POINTS,
diff --git a/libass/ass_font.c b/libass/ass_font.c
index 52e6d3a..0aeeec6 100644
--- a/libass/ass_font.c
+++ b/libass/ass_font.c
@@ -276,12 +276,93 @@ void ass_font_get_asc_desc(ass_font_t *font, uint32_t ch, int *asc,
*asc = *desc = 0;
}
+/*
+ * Strike a glyph with a horizontal line; it's possible to underline it
+ * and/or strike through it. For the line's position and size, truetype
+ * tables are consulted. Obviously this relies on the data in the tables
+ * being accurate.
+ *
+ */
+static int ass_strike_outline_glyph(FT_Face face, ass_font_t *font,
+ FT_Glyph glyph, int under, int through)
+{
+ TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
+ TT_Postscript *ps = FT_Get_Sfnt_Table(face, ft_sfnt_post);
+ FT_Outline *ol = &((FT_OutlineGlyph) glyph)->outline;
+ int bear, advance, y_scale, i;
+
+ // Grow outline
+ i = (under ? 4 : 0) + (through ? 4 : 0);
+ ol->points = realloc(ol->points, sizeof(FT_Vector) *
+ (ol->n_points + i));
+ ol->tags = realloc(ol->tags, ol->n_points + i);
+ i = !!under + !!through;
+ ol->contours = realloc(ol->contours, sizeof(short) *
+ (ol->n_contours + i));
+
+ // If the bearing is negative, the glyph starts left of the current
+ // pen position
+ bear = FFMIN(face->glyph->metrics.horiBearingX, 0);
+ // We're adding half a pixel to avoid small gaps
+ advance = d16_to_d6(glyph->advance.x) + 32;
+ y_scale = face->size->metrics.y_scale;
+
+ // Add points to the outline
+ if (under) {
+ int pos, size;
+ pos = FT_MulFix(ps->underlinePosition, y_scale * font->scale_y);
+ size = FT_MulFix(ps->underlineThickness,
+ y_scale * font->scale_y / 2);
+
+ if (pos > 0 || size <= 0)
+ return 0;
+
+ FT_Vector points[4] = {
+ {.x = bear, .y = pos + size},
+ {.x = advance, .y = pos + size},
+ {.x = advance, .y = pos - size},
+ {.x = bear, .y = pos - size},
+ };
+
+ for (i = 0; i < 4; i++) {
+ ol->points[ol->n_points] = points[i];
+ ol->tags[ol->n_points++] = 1;
+ }
+ ol->contours[ol->n_contours++] = ol->n_points - 1;
+ }
+
+ if (through) {
+ int pos, size;
+ pos = FT_MulFix(os2->yStrikeoutPosition, y_scale * font->scale_y);
+ size = FT_MulFix(os2->yStrikeoutSize, y_scale * font->scale_y / 2);
+
+ if (pos < 0 || size <= 0)
+ return 0;
+
+ FT_Vector points[4] = {
+ {.x = bear, .y = pos + size},
+ {.x = advance, .y = pos + size},
+ {.x = advance, .y = pos - size},
+ {.x = bear, .y = pos - size},
+ };
+
+ for (i = 0; i < 4; i++) {
+ ol->points[ol->n_points] = points[i];
+ ol->tags[ol->n_points++] = 1;
+ }
+
+ ol->contours[ol->n_contours++] = ol->n_points - 1;
+ }
+
+ return 1;
+}
+
/**
* \brief Get a glyph
* \param ch character code
**/
FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ass_font_t *font,
- uint32_t ch, ass_hinting_t hinting)
+ uint32_t ch, ass_hinting_t hinting, int deco)
{
int error;
int index = 0;
@@ -356,6 +437,9 @@ FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ass_font_t *font,
return 0;
}
+ ass_strike_outline_glyph(face, font, glyph, deco & DECO_UNDERLINE,
+ deco & DECO_STRIKETHROUGH);
+
return glyph;
}
diff --git a/libass/ass_font.h b/libass/ass_font.h
index b208064..8fe4c1e 100644
--- a/libass/ass_font.h
+++ b/libass/ass_font.h
@@ -27,6 +27,10 @@
#include "ass.h"
#include "ass_types.h"
+#define ASS_FONT_MAX_FACES 10
+#define DECO_UNDERLINE 1
+#define DECO_STRIKETHROUGH 2
+
typedef struct ass_font_desc_s {
char *family;
unsigned bold;
@@ -34,8 +38,6 @@ typedef struct ass_font_desc_s {
int treat_family_as_pattern;
} ass_font_desc_t;
-#define ASS_FONT_MAX_FACES 10
-
typedef struct ass_font_s {
ass_font_desc_t desc;
ass_library_t *library;
@@ -57,7 +59,7 @@ void ass_font_set_size(ass_font_t *font, double size);
void ass_font_get_asc_desc(ass_font_t *font, uint32_t ch, int *asc,
int *desc);
FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ass_font_t *font,
- uint32_t ch, ass_hinting_t hinting);
+ uint32_t ch, ass_hinting_t hinting, int flags);
FT_Vector ass_font_get_kerning(ass_font_t *font, uint32_t c1, uint32_t c2);
void ass_font_free(ass_font_t *font);
diff --git a/libass/ass_render.c b/libass/ass_render.c
index c112399..19870a5 100644
--- a/libass/ass_render.c
+++ b/libass/ass_render.c
@@ -144,6 +144,7 @@ typedef struct render_context_s {
ass_font_t *font;
char *font_path;
double font_size;
+ int flags; // decoration flags (underline/strike-through)
FT_Stroker stroker_x;
FT_Stroker stroker_y;
@@ -1561,6 +1562,18 @@ static char *parse_tag(ass_renderer_t *render_priv, char *p, double pwr)
} else
val = 0.;
render_priv->state.shadow_x = render_priv->state.shadow_y = val;
+ } else if (mystrcmp(&p, "s")) {
+ int val;
+ if (mystrtoi(&p, &val) && val)
+ render_priv->state.flags |= DECO_STRIKETHROUGH;
+ else
+ render_priv->state.flags &= ~DECO_STRIKETHROUGH;
+ } else if (mystrcmp(&p, "u")) {
+ int val;
+ if (mystrtoi(&p, &val) && val)
+ render_priv->state.flags |= DECO_UNDERLINE;
+ else
+ render_priv->state.flags &= ~DECO_UNDERLINE;
} else if (mystrcmp(&p, "pbo")) {
double val = 0;
if (mystrtod(&p, &val))
@@ -1716,6 +1729,9 @@ static void reset_render_context(ass_renderer_t *render_priv)
render_priv->state.c[1] = render_priv->state.style->SecondaryColour;
render_priv->state.c[2] = render_priv->state.style->OutlineColour;
render_priv->state.c[3] = render_priv->state.style->BackColour;
+ render_priv->state.flags =
+ (render_priv->state.style->Underline ? DECO_UNDERLINE : 0) |
+ (render_priv->state.style->StrikeOut ? DECO_STRIKETHROUGH : 0);
render_priv->state.font_size = render_priv->state.style->FontSize;
if (render_priv->state.family)
@@ -1904,6 +1920,7 @@ get_outline_glyph(ass_renderer_t *render_priv, int symbol,
key.advance = *advance;
key.outline.x = render_priv->state.border_x * 0xFFFF;
key.outline.y = render_priv->state.border_y * 0xFFFF;
+ key.flags = render_priv->state.flags;
}
memset(info, 0, sizeof(glyph_info_t));
@@ -1928,7 +1945,8 @@ get_outline_glyph(ass_renderer_t *render_priv, int symbol,
info->glyph =
ass_font_get_glyph(render_priv->fontconfig_priv,
render_priv->state.font, symbol,
- render_priv->settings.hinting);
+ render_priv->settings.hinting,
+ render_priv->state.flags);
}
if (!info->glyph)
return;