mesh: Add mesh pattern type and enum values

Add the mesh pattern type and an error status to be used to report an
incorrect construction of the pattern.

Update the backends to make them ready to handle the new pattern type,
even if it cannot be created yet.

1 files changed, 46 insertions, 0 deletions

diff --git a/src/cairo-types-private.h b/src/cairo-types-private.h
index 1282b3ff0..a09b410b2 100644
--- a/src/cairo-types-private.h
+++ b/src/cairo-types-private.h
@@ -442,6 +442,51 @@ typedef union {
     cairo_radial_pattern_t radial;
 } cairo_gradient_pattern_union_t;
 
+/*
+ * A mesh patch is a tensor-product patch (bicubic Bezier surface
+ * patch). It has 16 control points. Each set of 4 points along the
+ * sides of the 4x4 grid of control points is a Bezier curve that
+ * defines one side of the patch. A color is assigned to each
+ * corner. The inner 4 points provide additional control over the
+ * shape and the color mapping.
+ *
+ * Cairo uses the same convention as the PDF Reference for numbering
+ * the points and side of the patch.
+ *
+ *
+ *                      Side 1
+ *
+ *          p[0][3] p[1][3] p[2][3] p[3][3]
+ * Side 0   p[0][2] p[1][2] p[2][2] p[3][2]  Side 2
+ *          p[0][1] p[1][1] p[2][1] p[3][1]
+ *          p[0][0] p[1][0] p[2][0] p[3][0]
+ *
+ *                      Side 3
+ *
+ *
+ *   Point            Color
+ *  -------------------------
+ *  points[0][0]    colors[0]
+ *  points[0][3]    colors[1]
+ *  points[3][3]    colors[2]
+ *  points[3][0]    colors[3]
+ */
+
+typedef struct _cairo_mesh_patch {
+    cairo_point_double_t points[4][4];
+    cairo_color_t colors[4];
+} cairo_mesh_patch_t;
+
+typedef struct _cairo_mesh_pattern {
+    cairo_pattern_t base;
+
+    cairo_array_t patches;
+    cairo_mesh_patch_t *current_patch;
+    int current_side;
+    cairo_bool_t has_control_point[4];
+    cairo_bool_t has_color[4];
+} cairo_mesh_pattern_t;
+
 typedef union {
     cairo_pattern_type_t	    type;
     cairo_pattern_t		    base;
@@ -449,6 +494,7 @@ typedef union {
     cairo_solid_pattern_t	    solid;
     cairo_surface_pattern_t	    surface;
     cairo_gradient_pattern_union_t  gradient;
+    cairo_mesh_pattern_t	    mesh;
 } cairo_pattern_union_t;
 
 /*