2 * Copyright 2014 Google Inc.
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
8 #ifndef SkPatchGrid_DEFINED
9 #define SkPatchGrid_DEFINED
12 #include "SkPatchUtils.h"
13 #include "SkXfermode.h"
16 * Class that represents a grid of patches. Adjacent patches share their corners and a color is
17 * specified at each one of them. The colors are bilinearly interpolated across the patch.
19 * This implementation defines a bidimensional array of patches. There are 3 arrays to store the
20 * control points of the patches to avoid storing repeated data since there are several points
21 * shared between adjacent patches.
23 * The array fCornerPts stores the corner control points of the patches.
24 * The array fHrzPts holds the intermidiate control points of the top and bottom curves of a patch.
25 * The array fVrtPts holds the intermidiate control points of the left and right curves of a patch.
26 * The array fCornerColors holds the corner colors in the same format as fCornerPts.
27 * The array fTexCoords holds the texture coordinates in the same format as fCornerpts.
29 * fCornerPts fHrzPts fVrtPts
30 * -------------- ------------------- --------------
31 * | C0 | C1 | C2 | | H0 | H1 | H2 | H3 | | V0 | V1 | V2 |
32 * -------------- ------------------ ---------------
33 * | C3 | C4 | C5 | | H4 | H5 | H6 | H7 | | V4 | V5 | V6 |
34 * -------------- ------------------- --------------
35 * | C6 | C7 | C8 | | H8 | H9 | H10| H11| | V6 | V7 | V8 |
36 * -------------- ------------------- --------------
40 * With the above configuration we would have a 2x2 grid of patches:
43 * C0-------C1-------C2
48 * C3-H4-H5-C4-H6-H7-C5
53 * C6-------C7-------C8
57 * When trying to get a patch at a certain position it justs builds it with the corresponding
59 * When adding a patch it tries to add the points at their corresponding position trying to comply
60 * with the adjacent points or overwriting them.
62 * Based the idea on the SVG2 spec for mesh gradients in which a grid of patches is build as in the
63 * the following example:
64 * <meshGradient x="100" y="100">
68 * Up to four stops in first patch. See details below.
71 * Any number of meshPatches in row.
75 * Any number of meshRows, each with the same number of meshPatches as in the first row.
84 kNone_VertexType = 0X00,
85 kColors_VertexType = 0x01,
86 kTexs_VertexType = 0x02,
87 kColorsAndTexs_VertexType = 0x03
90 SkPatchGrid(int rows = 0, int cols = 0, VertexType flags = kNone_VertexType,
91 SkXfermode* xfer = NULL);
96 * Add a patch at location (x,y) overwriting the previous patch and shared points so they
97 * mantain C0 connectivity.
98 * The control points must be passed in a clockwise order starting at the top left corner.
99 * The colors and texCoords are the values at the corners of the patch which will be bilerp
100 * across it, they must also be in counterclockwise order starting at the top left corner.
102 bool setPatch(int x, int y, const SkPoint cubics[12], const SkColor colors[4],
103 const SkPoint texCoords[4]);
106 * Get patch at location (x,y). If cubics, colors or texCoords is not NULL it sets patch's
107 * array with its corresponding values.
108 * The function returns false if the cubics parameter is NULL or if the (x,y) coordinates are
109 * not within the range of the grid.
111 bool getPatch(int x, int y, SkPoint cubics[12], SkColor colors[4], SkPoint texCoords[4]) const;
114 * Resets the grid of patches to contain rows and cols of patches.
116 void reset(int rows, int cols, VertexType flags, SkXfermode* xMode);
119 * Draws the grid of patches. The patches are drawn starting at patch (0,0) drawing columns, so
120 * for a 2x2 grid the order would be (0,0)->(0,1)->(1,0)->(1,1). The order follows the order
121 * of the parametric coordinates of the coons patch.
123 void draw(SkCanvas* canvas, SkPaint& paint);
126 * Get the dimensions of the grid of patches.
128 SkISize getDimensions() const {
129 return SkISize::Make(fCols, fRows);
134 VertexType fModeFlags;
136 SkColor* fCornerColors;
138 SkPoint* fHrzCtrlPts;
139 SkPoint* fVrtCtrlPts;
140 SkXfermode* fXferMode;