static cairo_int_status_t
check_composite (const cairo_composite_rectangles_t *extents)
{
if (! _cairo_gl_operator_is_supported (extents->op))
return UNSUPPORTED ("unsupported operator");
return CAIRO_STATUS_SUCCESS;
}
cairo_int_status_t
_cairo_gl_check_composite_glyphs (const cairo_composite_rectangles_t *extents,
cairo_scaled_font_t *scaled_font,
cairo_glyph_t *glyphs,
int *num_glyphs)
{
if (! _cairo_gl_operator_is_supported (extents->op))
return UNSUPPORTED ("unsupported operator");
/* XXX use individual masks for large glyphs? */
if (ceil (scaled_font->max_scale) >= GLYPH_CACHE_MAX_SIZE)
return UNSUPPORTED ("glyphs too large");
return CAIRO_STATUS_SUCCESS;
}
cairo_bool_t
_cairo_gl_surface_check_span_renderer (cairo_operator_t op,
const cairo_pattern_t *pattern,
void *abstract_dst,
cairo_antialias_t antialias)
{
if (! _cairo_gl_operator_is_supported (op))
return FALSE;
return TRUE;
(void) pattern;
(void) abstract_dst;
(void) antialias;
}
cairo_status_t
_cairo_gl_composite_set_operator (cairo_gl_composite_t *setup,
cairo_operator_t op,
cairo_bool_t assume_component_alpha)
{
if (assume_component_alpha) {
if (op != CAIRO_OPERATOR_CLEAR &&
op != CAIRO_OPERATOR_OVER &&
op != CAIRO_OPERATOR_ADD)
return UNSUPPORTED ("unsupported component alpha operator");
} else {
if (! _cairo_gl_operator_is_supported (op))
return UNSUPPORTED ("unsupported operator");
}
setup->op = op;
return CAIRO_STATUS_SUCCESS;
}
cairo_int_status_t
_cairo_gl_surface_composite_trapezoids (cairo_operator_t op,
const cairo_pattern_t *pattern,
void *abstract_dst,
cairo_antialias_t antialias,
int src_x, int src_y,
int dst_x, int dst_y,
unsigned int width,
unsigned int height,
cairo_trapezoid_t *traps,
int num_traps,
cairo_region_t *clip_region)
{
cairo_gl_surface_t *dst = abstract_dst;
cairo_surface_pattern_t traps_pattern;
cairo_int_status_t status;
if (! _cairo_gl_operator_is_supported (op))
return UNSUPPORTED ("unsupported operator");
status = _cairo_gl_surface_deferred_clear (dst);
if (unlikely (status))
return status;
status = _cairo_gl_get_traps_pattern (dst,
dst_x, dst_y, width, height,
traps, num_traps, antialias,
&traps_pattern);
if (unlikely (status))
return status;
status = _cairo_gl_surface_composite (op,
pattern, &traps_pattern.base, dst,
src_x, src_y,
0, 0,
dst_x, dst_y,
width, height,
clip_region);
_cairo_pattern_fini (&traps_pattern.base);
assert (status != CAIRO_INT_STATUS_UNSUPPORTED);
return status;
}
cairo_status_t
_cairo_gl_composite_init (cairo_gl_composite_t *setup,
cairo_operator_t op,
cairo_gl_surface_t *dst,
cairo_bool_t assume_component_alpha)
{
memset (setup, 0, sizeof (cairo_gl_composite_t));
if (assume_component_alpha) {
if (op != CAIRO_OPERATOR_CLEAR &&
op != CAIRO_OPERATOR_OVER &&
op != CAIRO_OPERATOR_ADD)
return (cairo_status_t)UNSUPPORTED ("unsupported component alpha operator");
} else {
if (! _cairo_gl_operator_is_supported (op))
return (cairo_status_t)UNSUPPORTED ("unsupported operator");
}
setup->dst = dst;
setup->op = op;
setup->clip_region = dst->clip_region;
return CAIRO_STATUS_SUCCESS;
}
cairo_int_status_t
_cairo_gl_surface_show_glyphs (void *abstract_dst,
cairo_operator_t op,
const cairo_pattern_t *source,
cairo_glyph_t *glyphs,
int num_glyphs,
cairo_scaled_font_t *scaled_font,
cairo_clip_t *clip,
int *remaining_glyphs)
{
cairo_gl_surface_t *dst = abstract_dst;
cairo_rectangle_int_t surface_extents;
cairo_rectangle_int_t extents;
cairo_region_t *clip_region = NULL;
cairo_solid_pattern_t solid_pattern;
cairo_bool_t overlap, use_mask = FALSE;
cairo_status_t status;
if (! GLEW_ARB_vertex_buffer_object)
return UNSUPPORTED ("requires ARB_vertex_buffer_object");
if (! _cairo_gl_operator_is_supported (op))
return UNSUPPORTED ("unsupported operator");
if (! _cairo_operator_bounded_by_mask (op))
use_mask |= TRUE;
/* For CLEAR, cairo's rendering equation (quoting Owen's description in:
* http://lists.cairographics.org/archives/cairo/2005-August/004992.html)
* is:
* mask IN clip ? src OP dest : dest
* or more simply:
* mask IN CLIP ? 0 : dest
*
* where the ternary operator A ? B : C is (A * B) + ((1 - A) * C).
*
* The model we use in _cairo_gl_set_operator() is Render's:
* src IN mask IN clip OP dest
* which would boil down to:
* 0 (bounded by the extents of the drawing).
*
* However, we can do a Render operation using an opaque source
* and DEST_OUT to produce:
* 1 IN mask IN clip DEST_OUT dest
* which is
* mask IN clip ? 0 : dest
*/
if (op == CAIRO_OPERATOR_CLEAR) {
_cairo_pattern_init_solid (&solid_pattern, CAIRO_COLOR_WHITE,
CAIRO_CONTENT_COLOR);
source = &solid_pattern.base;
op = CAIRO_OPERATOR_DEST_OUT;
}
/* For SOURCE, cairo's rendering equation is:
* (mask IN clip) ? src OP dest : dest
* or more simply:
* (mask IN clip) ? src : dest.
*
* If we just used the Render equation, we would get:
* (src IN mask IN clip) OP dest
* or:
* (src IN mask IN clip) bounded by extents of the drawing.
*
* The trick is that for GL blending, we only get our 4 source values
* into the blender, and since we need all 4 components of source, we
* can't also get the mask IN clip into the blender. But if we did
* two passes we could make it work:
* dest = (mask IN clip) DEST_OUT dest
* dest = src IN mask IN clip ADD dest
*
* But for now, composite via an intermediate mask.
*/
if (op == CAIRO_OPERATOR_SOURCE)
use_mask |= TRUE;
/* XXX we don't need ownership of the font as we use a global
* glyph cache -- but we do need scaled_glyph eviction notification. :-(
*/
if (! _cairo_gl_surface_owns_font (dst, scaled_font))
return UNSUPPORTED ("do not control font");
/* If the glyphs overlap, we need to build an intermediate mask rather
* then perform the compositing directly.
*/
status = _cairo_scaled_font_glyph_device_extents (scaled_font,
glyphs, num_glyphs,
&extents,
&overlap);
if (unlikely (status))
return status;
use_mask |= overlap;
if (clip != NULL) {
status = _cairo_clip_get_region (clip, &clip_region);
/* the empty clip should never be propagated this far */
assert (status != CAIRO_INT_STATUS_NOTHING_TO_DO);
if (unlikely (_cairo_status_is_error (status)))
return status;
use_mask |= status == CAIRO_INT_STATUS_UNSUPPORTED;
if (! _cairo_rectangle_intersect (&extents,
_cairo_clip_get_extents (clip)))
goto EMPTY;
}
surface_extents.x = surface_extents.y = 0;
surface_extents.width = dst->width;
surface_extents.height = dst->height;
if (! _cairo_rectangle_intersect (&extents, &surface_extents))
goto EMPTY;
if (use_mask) {
return _cairo_gl_surface_show_glyphs_via_mask (dst, op,
source,
glyphs, num_glyphs,
&extents,
scaled_font,
clip,
remaining_glyphs);
}
return _render_glyphs (dst, extents.x, extents.y,
op, source,
glyphs, num_glyphs, &extents,
scaled_font, clip_region, remaining_glyphs);
EMPTY:
*remaining_glyphs = 0;
if (! _cairo_operator_bounded_by_mask (op))
return _cairo_surface_paint (&dst->base, op, source, clip);
else
return CAIRO_STATUS_SUCCESS;
}
