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https://gitlab.freedesktop.org/cairo/cairo.git
synced 2026-05-05 15:48:00 +02:00
[cairo-spans] Implement a span renderer for cairo_image_surface_t.
This implementation first produces an A8 alpha mask and then pixman_image_composites the result to the destination with the source. Clipping is handled by pixman when it is region clipping or by cairo-surface-fallback when it is something more complex.
This commit is contained in:
M Joonas Pihlaja
parent
7994fc06ad
commit
85b81a3e59
1 changed files with 233 additions and 40 deletions
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@ -1078,6 +1078,15 @@ _cairo_image_surface_fill_rectangles (void *abstract_surface,
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return status;
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}
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static cairo_format_t
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_cairo_mask_format_from_antialias (cairo_antialias_t antialias)
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{
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if (antialias == CAIRO_ANTIALIAS_NONE)
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return CAIRO_FORMAT_A1;
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return CAIRO_FORMAT_A8;
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}
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static cairo_int_status_t
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_cairo_image_surface_composite_trapezoids (cairo_operator_t op,
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const cairo_pattern_t *pattern,
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@ -1095,13 +1104,10 @@ _cairo_image_surface_composite_trapezoids (cairo_operator_t op,
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cairo_surface_attributes_t attributes;
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cairo_image_surface_t *dst = abstract_dst;
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cairo_image_surface_t *src;
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cairo_int_status_t status;
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pixman_image_t *mask;
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pixman_format_code_t format;
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uint32_t *mask_data;
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cairo_int_status_t status;
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cairo_image_surface_t *mask = NULL;
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pixman_trapezoid_t stack_traps[CAIRO_STACK_ARRAY_LENGTH (pixman_trapezoid_t)];
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pixman_trapezoid_t *pixman_traps = stack_traps;
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int mask_stride;
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int i;
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if (height == 0 || width == 0)
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@ -1165,40 +1171,19 @@ _cairo_image_surface_composite_trapezoids (cairo_operator_t op,
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if (unlikely (status))
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goto CLEANUP_SOURCE;
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switch (antialias) {
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case CAIRO_ANTIALIAS_NONE:
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format = PIXMAN_a1;
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mask_stride = ((width + 31) / 8) & ~0x03;
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break;
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case CAIRO_ANTIALIAS_GRAY:
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case CAIRO_ANTIALIAS_SUBPIXEL:
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case CAIRO_ANTIALIAS_DEFAULT:
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default:
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format = PIXMAN_a8;
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mask_stride = (width + 3) & ~3;
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break;
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}
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/* The image must be initially transparent */
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mask_data = calloc (mask_stride, height);
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if (unlikely (mask_data == NULL)) {
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status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
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mask = (cairo_image_surface_t *)
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cairo_image_surface_create (
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_cairo_mask_format_from_antialias (antialias),
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width, height);
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if (cairo_surface_status (&mask->base) != CAIRO_STATUS_SUCCESS)
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goto CLEANUP_SOURCE;
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}
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mask = pixman_image_create_bits (format, width, height,
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mask_data, mask_stride);
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if (unlikely (mask == NULL)) {
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status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
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goto CLEANUP_IMAGE_DATA;
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}
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pixman_add_trapezoids (mask, - dst_x, - dst_y,
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pixman_add_trapezoids (mask->pixman_image, - dst_x, - dst_y,
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num_traps, pixman_traps);
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pixman_image_composite (_pixman_operator (op),
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src->pixman_image,
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mask,
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mask->pixman_image,
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dst->pixman_image,
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src_x + attributes.x_offset,
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src_y + attributes.y_offset,
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@ -1208,15 +1193,13 @@ _cairo_image_surface_composite_trapezoids (cairo_operator_t op,
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if (! _cairo_operator_bounded_by_mask (op))
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status = _cairo_surface_composite_shape_fixup_unbounded (&dst->base,
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&attributes, src->width, src->height,
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&attributes,
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src->width, src->height,
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width, height,
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src_x, src_y,
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0, 0,
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dst_x, dst_y, width, height);
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pixman_image_unref (mask);
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CLEANUP_IMAGE_DATA:
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free (mask_data);
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cairo_surface_destroy (&mask->base);
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CLEANUP_SOURCE:
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_cairo_pattern_release_surface (pattern, &src->base, &attributes);
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@ -1228,6 +1211,216 @@ _cairo_image_surface_composite_trapezoids (cairo_operator_t op,
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return status;
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}
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typedef struct _cairo_image_surface_span_renderer {
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cairo_span_renderer_t base;
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cairo_operator_t op;
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const cairo_pattern_t *pattern;
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cairo_antialias_t antialias;
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cairo_image_surface_t *src;
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cairo_surface_attributes_t src_attributes;
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cairo_image_surface_t *mask;
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cairo_image_surface_t *dst;
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cairo_composite_rectangles_t composite_rectangles;
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} cairo_image_surface_span_renderer_t;
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static cairo_status_t
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_cairo_image_surface_span_renderer_render_row (
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void *abstract_renderer,
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int y,
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const cairo_half_open_span_t *spans,
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unsigned num_spans)
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{
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cairo_image_surface_span_renderer_t *renderer = abstract_renderer;
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int xmin = renderer->composite_rectangles.mask.x;
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int xmax = xmin + renderer->composite_rectangles.width;
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uint8_t *row;
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int prev_x = xmin;
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int prev_alpha = 0;
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unsigned i;
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/* Make sure we're within y-range. */
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y -= renderer->composite_rectangles.mask.y;
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if (y < 0 || y >= renderer->composite_rectangles.height)
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return CAIRO_STATUS_SUCCESS;
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row = (uint8_t*)(renderer->mask->data) + y*(size_t)renderer->mask->stride - xmin;
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/* Find the first span within x-range. */
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for (i=0; i < num_spans && spans[i].x < xmin; i++) {}
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if (i>0)
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prev_alpha = spans[i-1].coverage;
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/* Set the intermediate spans. */
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for (; i < num_spans; i++) {
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int x = spans[i].x;
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if (x >= xmax)
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break;
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if (prev_alpha != 0) {
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/* We implement setting rendering the most common single
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* pixel wide span case to avoid the overhead of a memset
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* call. Open coding setting longer spans didn't show a
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* noticeable improvement over memset. */
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if (x == prev_x + 1) {
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row[prev_x] = prev_alpha;
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}
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else {
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memset(row + prev_x, prev_alpha, x - prev_x);
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}
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}
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prev_x = x;
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prev_alpha = spans[i].coverage;
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}
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if (prev_alpha != 0 && prev_x < xmax) {
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memset(row + prev_x, prev_alpha, xmax - prev_x);
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}
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return CAIRO_STATUS_SUCCESS;
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}
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static void
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_cairo_image_surface_span_renderer_destroy (void *abstract_renderer)
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{
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cairo_image_surface_span_renderer_t *renderer = abstract_renderer;
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if (!renderer) return;
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if (renderer->src != NULL) {
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_cairo_pattern_release_surface (renderer->pattern,
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&renderer->src->base,
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&renderer->src_attributes);
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}
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if (renderer->mask != NULL)
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cairo_surface_destroy (&renderer->mask->base);
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free (renderer);
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}
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static cairo_status_t
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_cairo_image_surface_span_renderer_finish (void *abstract_renderer)
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{
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cairo_image_surface_span_renderer_t *renderer = abstract_renderer;
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cairo_status_t status = CAIRO_STATUS_SUCCESS;
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if (renderer->src == NULL || renderer->mask == NULL)
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return CAIRO_STATUS_SUCCESS;
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status = cairo_surface_status (&renderer->mask->base);
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if (status == CAIRO_STATUS_SUCCESS) {
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cairo_composite_rectangles_t *rects = &renderer->composite_rectangles;
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cairo_image_surface_t *src = renderer->src;
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cairo_image_surface_t *dst = renderer->dst;
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cairo_surface_attributes_t *src_attributes = &renderer->src_attributes;
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int width = rects->width;
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int height = rects->height;
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pixman_image_composite (_pixman_operator (renderer->op),
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src->pixman_image,
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renderer->mask->pixman_image,
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dst->pixman_image,
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rects->src.x + src_attributes->x_offset,
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rects->src.y + src_attributes->y_offset,
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0, 0, /* mask.x, mask.y */
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rects->dst.x, rects->dst.y,
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width, height);
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if (! _cairo_operator_bounded_by_mask (renderer->op))
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status = _cairo_surface_composite_shape_fixup_unbounded (
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&dst->base,
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src_attributes,
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src->width, src->height,
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rects->width, rects->height,
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rects->src.x, rects->src.y,
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0, 0, /* mask.x, mask.y */
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rects->dst.x, rects->dst.y,
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rects->width, rects->height);
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}
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if (status != CAIRO_STATUS_SUCCESS)
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return _cairo_span_renderer_set_error (abstract_renderer,
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status);
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return CAIRO_STATUS_SUCCESS;
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}
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static cairo_bool_t
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_cairo_image_surface_check_span_renderer (cairo_operator_t op,
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const cairo_pattern_t *pattern,
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void *abstract_dst,
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cairo_antialias_t antialias,
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const cairo_composite_rectangles_t *rects)
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{
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(void) op;
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(void) pattern;
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(void) abstract_dst;
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(void) antialias;
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(void) rects;
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return TRUE;
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}
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static cairo_span_renderer_t *
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_cairo_image_surface_create_span_renderer (cairo_operator_t op,
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const cairo_pattern_t *pattern,
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void *abstract_dst,
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cairo_antialias_t antialias,
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const cairo_composite_rectangles_t *rects)
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{
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cairo_image_surface_t *dst = abstract_dst;
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cairo_image_surface_span_renderer_t *renderer
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= calloc(1, sizeof(*renderer));
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cairo_status_t status;
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int width = rects->width;
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int height = rects->height;
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if (renderer == NULL)
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return _cairo_span_renderer_create_in_error (CAIRO_STATUS_NO_MEMORY);
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renderer->base.destroy = _cairo_image_surface_span_renderer_destroy;
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renderer->base.finish = _cairo_image_surface_span_renderer_finish;
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renderer->base.render_row =
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_cairo_image_surface_span_renderer_render_row;
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renderer->op = op;
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renderer->pattern = pattern;
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renderer->antialias = antialias;
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renderer->dst = dst;
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renderer->composite_rectangles = *rects;
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status = _cairo_pattern_acquire_surface (
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renderer->pattern, &renderer->dst->base,
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rects->src.x, rects->src.y,
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width, height,
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(cairo_surface_t **) &renderer->src,
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&renderer->src_attributes);
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if (status)
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goto unwind;
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status = _cairo_image_surface_set_attributes (
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renderer->src, &renderer->src_attributes,
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rects->dst.x + width/2, rects->dst.y + height/2);
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if (status)
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goto unwind;
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/* TODO: support rendering to A1 surfaces (or: go add span
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* compositing to pixman.) */
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renderer->mask = (cairo_image_surface_t *)
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cairo_image_surface_create (CAIRO_FORMAT_A8,
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width, height);
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status = cairo_surface_status (&renderer->mask->base);
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unwind:
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if (status != CAIRO_STATUS_SUCCESS) {
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_cairo_image_surface_span_renderer_destroy (renderer);
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return _cairo_span_renderer_create_in_error (status);
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}
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return &renderer->base;
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}
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cairo_int_status_t
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_cairo_image_surface_set_clip_region (void *abstract_surface,
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cairo_region_t *region)
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@ -1303,8 +1496,8 @@ const cairo_surface_backend_t _cairo_image_surface_backend = {
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_cairo_image_surface_composite,
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_cairo_image_surface_fill_rectangles,
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_cairo_image_surface_composite_trapezoids,
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NULL, /* create_span_renderer */
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NULL, /* check_span_renderer */
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_cairo_image_surface_create_span_renderer,
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_cairo_image_surface_check_span_renderer,
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NULL, /* copy_page */
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NULL, /* show_page */
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_cairo_image_surface_set_clip_region,
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