Add pixman_composite_trapezoids().

This function is an implementation of the X server request
Trapezoids. That request is what the X backend of cairo is using all
the time; by moving it into pixman we can hopefully make it faster.

diff --git a/pixman/pixman-trap.c b/pixman/pixman-trap.c
index 742911c..ecec5d4 100644 (file)
--- a/pixman/pixman-trap.c
+++ b/pixman/pixman-trap.c
@@ -384,3 +384,90 @@ pixman_rasterize_trapezoid (pixman_image_t *          image,
        pixman_rasterize_edges (image, &l, &r, t, b);
     }
 }
+
+PIXMAN_EXPORT void
+pixman_composite_trapezoids (pixman_op_t               op,
+                            pixman_image_t *           src,
+                            pixman_image_t *           dst,
+                            pixman_format_code_t       mask_format,
+                            int                        x_src,
+                            int                        y_src,
+                            int                        x_dst,
+                            int                        y_dst,
+                            int                        n_traps,
+                            const pixman_trapezoid_t * traps)
+{
+    pixman_image_t *tmp;
+    pixman_box32_t box;
+    int i;
+    int x_rel, y_rel;
+
+    if (n_traps <= 0)
+       return;
+
+    _pixman_image_validate (src);
+    _pixman_image_validate (dst);
+
+    box.x1 = INT32_MAX;
+    box.y1 = INT32_MAX;
+    box.x2 = INT32_MIN;
+    box.y2 = INT32_MIN;
+    
+    for (i = 0; i < n_traps; ++i)
+    {
+       const pixman_trapezoid_t *trap = &(traps[i]);
+       int y1, y2;
+
+       if (!pixman_trapezoid_valid (trap))
+           continue;
+       
+       y1 = pixman_fixed_to_int (trap->top);
+       if (y1 < box.y1)
+           box.y1 = y1;
+       
+       y2 = pixman_fixed_to_int (pixman_fixed_ceil (trap->bottom));
+       if (y2 > box.y2)
+           box.y2 = y2;
+
+#define EXTEND_MIN(x)                                                  \
+       if (pixman_fixed_to_int ((x)) < box.x1)                         \
+           box.x1 = pixman_fixed_to_int ((x));
+#define EXTEND_MAX(x)                                                  \
+       if (pixman_fixed_to_int (pixman_fixed_ceil ((x))) > box.x2)     \
+           box.x2 = pixman_fixed_to_int (pixman_fixed_ceil ((x)));
+
+#define EXTEND(x)                                                      \
+       EXTEND_MIN(x);                                                  \
+       EXTEND_MAX(x);
+
+       EXTEND(trap->left.p1.x);
+       EXTEND(trap->left.p2.x);
+       EXTEND(trap->right.p1.x);
+       EXTEND(trap->right.p2.x);
+    }
+
+    if (box.x1 >= box.x2 || box.y1 >= box.y2)
+       return;
+    
+    tmp = pixman_image_create_bits (
+       mask_format, box.x2 - box.x1, box.y2 - box.y1, NULL, -1);
+       
+    for (i = 0; i < n_traps; ++i)
+    {
+       const pixman_trapezoid_t *trap = &(traps[i]);
+
+       if (!pixman_trapezoid_valid (trap))
+           continue;
+
+       pixman_rasterize_trapezoid (tmp, trap, - box.x1, - box.y1);
+    }
+
+    x_rel = box.x1 + x_src - x_dst;
+    y_rel = box.y1 + y_src - y_dst;
+
+    pixman_image_composite (op, src, tmp, dst,
+                           x_rel, y_rel, 0, 0, box.x1, box.y1,
+                           box.x2 - box.x1, box.y2 - box.y1);
+
+    pixman_image_unref (tmp);
+}

diff --git a/pixman/pixman.h b/pixman/pixman.h
index b95d0e9..52ab8a5 100644 (file)
--- a/pixman/pixman.h
+++ b/pixman/pixman.h
@@ -950,7 +950,17 @@ void           pixman_rasterize_trapezoid  (pixman_image_t            *image,
                                            const pixman_trapezoid_t  *trap,
                                            int                        x_off,
                                            int                        y_off);
-
+void          pixman_composite_trapezoids (pixman_op_t                op,
+                                          pixman_image_t *            src,
+                                          pixman_image_t *            dst,
+                                          pixman_format_code_t        mask_format,
+                                          int                         x_src,
+                                          int                         y_src,
+                                          int                         x_dst,
+                                          int                         y_dst,
+                                          int                         n_traps,
+                                          const pixman_trapezoid_t *  traps);
+    
 PIXMAN_END_DECLS
 
 #endif /* PIXMAN_H__ */