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Protect against division by zero in various places. (http://bugzilla.gnome.org/show_bug.cgi?id=311299, reported by Ali Akcaag

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This commit is contained in:
Owen Taylor 2005-07-22 15:15:15 +00:00
parent 5fb1c80333
commit 399b00a99b
2 changed files with 55 additions and 20 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2005-07-22 Owen Taylor <otaylor@redhat.com>
* src/cairo-ft-font.c: Protect against division by zero in various places.
(http://bugzilla.gnome.org/show_bug.cgi?id=311299, reported by Ali Akcaagac)
2005-07-22 Owen Taylor <otaylor@redhat.com> 2005-07-22 Owen Taylor <otaylor@redhat.com>
Patch from Tor Lillqvist <tml@novell.com> Patch from Tor Lillqvist <tml@novell.com>

70
src/cairo-ft-font.c
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@ -459,11 +459,18 @@ _compute_transform (ft_font_transform_t *sf,
_cairo_matrix_compute_scale_factors (&normalized, _cairo_matrix_compute_scale_factors (&normalized,
&sf->x_scale, &sf->y_scale, &sf->x_scale, &sf->y_scale,
/* XXX */ 1); /* XXX */ 1);
cairo_matrix_scale (&normalized, 1.0 / sf->x_scale, 1.0 / sf->y_scale);
_cairo_matrix_get_affine (&normalized, if (sf->x_scale != 0 && sf->y_scale != 0) {
&sf->shape[0][0], &sf->shape[0][1], cairo_matrix_scale (&normalized, 1.0 / sf->x_scale, 1.0 / sf->y_scale);
&sf->shape[1][0], &sf->shape[1][1],
&tx, &ty); _cairo_matrix_get_affine (&normalized,
&sf->shape[0][0], &sf->shape[0][1],
&sf->shape[1][0], &sf->shape[1][1],
&tx, &ty);
} else {
sf->shape[0][0] = sf->shape[1][1] = 1.0;
sf->shape[0][1] = sf->shape[1][0] = 0.0;
}
} }
/* Temporarily scales an unscaled font to the give scale. We catch /* Temporarily scales an unscaled font to the give scale. We catch
@ -1091,6 +1098,7 @@ _cairo_ft_unscaled_font_create_glyph (void *abstract_
FT_Face face; FT_Face face;
FT_Glyph_Metrics *metrics; FT_Glyph_Metrics *metrics;
cairo_status_t status = CAIRO_STATUS_SUCCESS; cairo_status_t status = CAIRO_STATUS_SUCCESS;
double x_factor, y_factor;
face = _ft_unscaled_font_lock_face (unscaled); face = _ft_unscaled_font_lock_face (unscaled);
if (!face) if (!face)
@ -1106,6 +1114,16 @@ _cairo_ft_unscaled_font_create_glyph (void *abstract_
goto FAIL; goto FAIL;
} }
if (unscaled->x_scale == 0)
x_factor = 0;
else
x_factor = 1 / unscaled->x_scale;
if (unscaled->y_scale == 0)
y_factor = 0;
else
y_factor = 1 / unscaled->y_scale;
/* /*
* Note: the font's coordinate system is upside down from ours, so the * Note: the font's coordinate system is upside down from ours, so the
* Y coordinates of the bearing and advance need to be negated. * Y coordinates of the bearing and advance need to be negated.
@ -1130,27 +1148,27 @@ _cairo_ft_unscaled_font_create_glyph (void *abstract_
advance = ((metrics->horiAdvance + 32) & -64); advance = ((metrics->horiAdvance + 32) & -64);
val->extents.x_bearing = DOUBLE_FROM_26_6 (x1) / unscaled->x_scale; val->extents.x_bearing = DOUBLE_FROM_26_6 (x1) * x_factor;
val->extents.y_bearing = -DOUBLE_FROM_26_6 (y1) / unscaled->y_scale; val->extents.y_bearing = -DOUBLE_FROM_26_6 (y1) * y_factor;
val->extents.width = DOUBLE_FROM_26_6 (x2 - x1) / unscaled->x_scale; val->extents.width = DOUBLE_FROM_26_6 (x2 - x1) * x_factor;
val->extents.height = DOUBLE_FROM_26_6 (y2 - y1) / unscaled->y_scale; val->extents.height = DOUBLE_FROM_26_6 (y2 - y1) * y_factor;
/* /*
* use untransformed advance values * use untransformed advance values
* XXX uses horizontal advance only at present; should provide FT_LOAD_VERTICAL_LAYOUT * XXX uses horizontal advance only at present; should provide FT_LOAD_VERTICAL_LAYOUT
*/ */
val->extents.x_advance = DOUBLE_FROM_26_6 (advance) / unscaled->x_scale; val->extents.x_advance = DOUBLE_FROM_26_6 (advance) * x_factor;
val->extents.y_advance = 0; val->extents.y_advance = 0;
} else { } else {
val->extents.x_bearing = DOUBLE_FROM_26_6 (metrics->horiBearingX) / unscaled->x_scale; val->extents.x_bearing = DOUBLE_FROM_26_6 (metrics->horiBearingX) * x_factor;
val->extents.y_bearing = -DOUBLE_FROM_26_6 (metrics->horiBearingY) / unscaled->y_scale; val->extents.y_bearing = -DOUBLE_FROM_26_6 (metrics->horiBearingY) * y_factor;
val->extents.width = DOUBLE_FROM_26_6 (metrics->width) / unscaled->x_scale; val->extents.width = DOUBLE_FROM_26_6 (metrics->width) * x_factor;
val->extents.height = DOUBLE_FROM_26_6 (metrics->height) / unscaled->y_scale; val->extents.height = DOUBLE_FROM_26_6 (metrics->height) * y_factor;
val->extents.x_advance = DOUBLE_FROM_26_6 (face->glyph->metrics.horiAdvance) / unscaled->x_scale; val->extents.x_advance = DOUBLE_FROM_26_6 (face->glyph->metrics.horiAdvance) * x_factor;
val->extents.y_advance = 0 / unscaled->y_scale; val->extents.y_advance = 0 * y_factor;
} }
if (glyphslot->format == FT_GLYPH_FORMAT_OUTLINE) if (glyphslot->format == FT_GLYPH_FORMAT_OUTLINE)
@ -1571,10 +1589,22 @@ _cairo_ft_scaled_font_font_extents (void *abstract_font,
* user space * user space
*/ */
if (scaled_font->options.hint_metrics != CAIRO_HINT_METRICS_OFF) { if (scaled_font->options.hint_metrics != CAIRO_HINT_METRICS_OFF) {
extents->ascent = DOUBLE_FROM_26_6(metrics->ascender) / scaled_font->unscaled->y_scale; double x_factor, y_factor;
extents->descent = DOUBLE_FROM_26_6(- metrics->descender) / scaled_font->unscaled->y_scale;
extents->height = DOUBLE_FROM_26_6(metrics->height) / scaled_font->unscaled->y_scale; if (scaled_font->unscaled->x_scale == 0)
extents->max_x_advance = DOUBLE_FROM_26_6(metrics->max_advance) / scaled_font->unscaled->x_scale; x_factor = 0;
else
x_factor = 1 / scaled_font->unscaled->x_scale;
if (scaled_font->unscaled->y_scale == 0)
y_factor = 0;
else
y_factor = 1 / scaled_font->unscaled->y_scale;
extents->ascent = DOUBLE_FROM_26_6(metrics->ascender) * y_factor;
extents->descent = DOUBLE_FROM_26_6(- metrics->descender) * y_factor;
extents->height = DOUBLE_FROM_26_6(metrics->height) * y_factor;
extents->max_x_advance = DOUBLE_FROM_26_6(metrics->max_advance) * x_factor;
} else { } else {
double scale = face->units_per_EM; double scale = face->units_per_EM;