Attachment 134165 Details for Bug 102661 – [PATCH] Hacky hack: Use color glyph alpha as mask

[patch] [PATCH] Hacky hack: Use color glyph alpha as mask

0001-Hacky-hack-Use-color-glyph-alpha-as-mask.patch (text/plain), 5.97 KB, created by Jan Alexander Steffens (heftig) on 2017-09-11 18:04:45 UTC

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Creator: Jan Alexander Steffens (heftig)

Created: 2017-09-11 18:04:45 UTC

Size: 5.97 KB

patch

obsolete

>From 9eba3c899c4d6e91b69ebf93aeca386e77eb8638 Mon Sep 17 00:00:00 2001
>Message-Id: <9eba3c899c4d6e91b69ebf93aeca386e77eb8638.1505152993.git.jan.steffens@gmail.com>
>From: "Jan Alexander Steffens (heftig)" <jan.steffens@gmail.com>
>Date: Mon, 11 Sep 2017 19:46:06 +0200
>Subject: [PATCH] Hacky hack: Use color glyph alpha as mask
>
>- When loading a color glyph, separate the alpha channel and save it as
>  the non-color surface.
>- Use the non-color surface as the mask when compositing color glyphs.
>- Plug a leak of patterns in composite_one_color_glyph
>
>=> Drawing glyphs with CAIRO_OPERATOR_SOURCE no longer clears dest. In
>   general the handling of color glyphs should match the handling of
>   normal glyphs now, except for the source color.
>
>=> Possible extension: Let the user deactivate color glyph handling (in
>   the context? in the pattern?) in order to draw with the chosen source
>   instead, for things like text shadows. Since the normal surface is the
>   alpha mask now, this handles color glyphs nicely.
>
>   To do that, just have it override the check of
>   _cairo_scaled_font_has_color_glyphs to be false.
>
>My ignorance of cairo and pixman internals means this is probably
>terrible code.
>---
> src/cairo-ft-font.c | 34 +++++++++++++++++++++++++++++++++-
> src/cairo-surface.c | 19 ++++++++++++-------
> 2 files changed, 45 insertions(+), 8 deletions(-)
>
>diff --git a/src/cairo-ft-font.c b/src/cairo-ft-font.c
>index 3b3087578927e54e..2f9aff2defb444e5 100644
>--- a/src/cairo-ft-font.c
>+++ b/src/cairo-ft-font.c
>@@ -2475,9 +2475,41 @@ LOAD:
> 
>         if (pixman_image_get_format (surface->pixman_image) == PIXMAN_a8r8g8b8 &&
>             !pixman_image_get_component_alpha (surface->pixman_image)) {
>+            cairo_surface_t *alpha_surface, *color_surface;
>+            cairo_pattern_t *pattern;
>+
>+            /* XXX: HACK */
>+            alpha_surface = cairo_image_surface_create (CAIRO_FORMAT_A8,
>+                                                        surface->width,
>+                                                        surface->height);
>+            color_surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24,
>+                                                        surface->width,
>+                                                        surface->height);
>+            pattern = cairo_pattern_create_for_surface (&surface->base);
>+            status |= alpha_surface->backend->paint (alpha_surface, CAIRO_OPERATOR_SOURCE, pattern, NULL);
>+            status |= color_surface->backend->paint (color_surface, CAIRO_OPERATOR_SOURCE, pattern, NULL);
>+            cairo_surface_set_device_offset (color_surface,
>+                                             surface->base.device_transform.x0,
>+                                             surface->base.device_transform.y0);
>+            cairo_surface_set_device_offset (alpha_surface,
>+                                             surface->base.device_transform.x0,
>+                                             surface->base.device_transform.y0);
>+            cairo_surface_destroy (&surface->base);
>+            cairo_pattern_destroy (pattern);
>+
>+            if (unlikely (status)) {
>+                cairo_surface_destroy (alpha_surface);
>+                cairo_surface_destroy (color_surface);
>+                goto FAIL;
>+            }
>+
>+            _cairo_scaled_glyph_set_surface (scaled_glyph,
>+                                             &scaled_font->base,
>+                                             (cairo_image_surface_t *) alpha_surface);
>+
>             _cairo_scaled_glyph_set_color_surface (scaled_glyph,
>                                                    &scaled_font->base,
>-                                                   surface);
>+                                                   (cairo_image_surface_t *) color_surface);
>         } else {
>             _cairo_scaled_glyph_set_surface (scaled_glyph,
>                                              &scaled_font->base,
>diff --git a/src/cairo-surface.c b/src/cairo-surface.c
>index 6f25bd7c044f2400..49fcd9f8dfcbcdf0 100644
>--- a/src/cairo-surface.c
>+++ b/src/cairo-surface.c
>@@ -2547,31 +2547,36 @@ ensure_scaled_glyph (cairo_scaled_font_t   *scaled_font,
> static inline cairo_int_status_t
> composite_one_color_glyph (cairo_surface_t       *surface,
>                            cairo_operator_t       op,
>-                           const cairo_pattern_t *source,
>+                           const cairo_pattern_t *unused_source,
>                            const cairo_clip_t    *clip,
>                            cairo_glyph_t         *glyph,
>                            cairo_scaled_glyph_t  *scaled_glyph)
> {
>     cairo_int_status_t status;
>     cairo_image_surface_t *glyph_surface;
>-    cairo_pattern_t *pattern;
>-    cairo_matrix_t matrix;
> 
>     status = CAIRO_INT_STATUS_SUCCESS;
> 
>-    glyph_surface = scaled_glyph->color_surface;
>+    glyph_surface = scaled_glyph->surface;
> 
>     if (glyph_surface->width && glyph_surface->height) {
>+        cairo_pattern_t *source, *mask;
>+        cairo_matrix_t matrix;
>         int x, y;
>+
>         /* round glyph locations to the nearest pixels */
>         /* XXX: FRAGILE: We're ignoring device_transform scaling here. A bug? */
> 	x = _cairo_lround (glyph->x - glyph_surface->base.device_transform.x0);
> 	y = _cairo_lround (glyph->y - glyph_surface->base.device_transform.y0);
> 
>-        pattern = cairo_pattern_create_for_surface ((cairo_surface_t *)glyph_surface);
>+        source = cairo_pattern_create_for_surface (&scaled_glyph->color_surface->base);
>+        mask = cairo_pattern_create_for_surface (&glyph_surface->base);
>         cairo_matrix_init_translate (&matrix, - x, - y);
>-        cairo_pattern_set_matrix (pattern, &matrix);
>-        status = surface->backend->paint (surface, op, pattern, clip);
>+        cairo_pattern_set_matrix (source, &matrix);
>+        cairo_pattern_set_matrix (mask, &matrix);
>+        status = surface->backend->mask (surface, op, source, mask, clip);
>+        cairo_pattern_destroy (source);
>+        cairo_pattern_destroy (mask);
>     }
> 
>     return status;
>-- 
>2.14.1
>

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