xref: /aosp_15_r20/external/skia/src/gpu/RectanizerSkyline.h (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 /*
2  * Copyright 2014 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef skgpu_RectanizerSkyline_DEFINED
9 #define skgpu_RectanizerSkyline_DEFINED
10 
11 #include "include/private/base/SkTDArray.h"
12 #include "src/gpu/Rectanizer.h"
13 
14 #include <cstdint>
15 
16 struct SkIPoint16;
17 
18 namespace skgpu {
19 
20 // Pack rectangles and track the current silhouette
21 // Based, in part, on Jukka Jylanki's work at http://clb.demon.fi
22 //
23 // Mark this class final in an effort to avoid the vtable when this subclass is used explicitly.
24 class RectanizerSkyline final : public Rectanizer {
25 public:
RectanizerSkyline(int w,int h)26     RectanizerSkyline(int w, int h) : Rectanizer(w, h) {
27         this->reset();
28     }
29 
~RectanizerSkyline()30     ~RectanizerSkyline() final { }
31 
reset()32     void reset() final {
33         fAreaSoFar = 0;
34         fSkyline.clear();
35         fSkyline.push_back(SkylineSegment{0, 0, this->width()});
36     }
37 
38     bool addRect(int w, int h, SkIPoint16* loc) final;
39 
percentFull()40     float percentFull() const final {
41         return fAreaSoFar / ((float)this->width() * this->height());
42     }
43 
44 private:
45     struct SkylineSegment {
46         int  fX;
47         int  fY;
48         int  fWidth;
49     };
50 
51     SkTDArray<SkylineSegment> fSkyline;
52 
53     int32_t fAreaSoFar;
54 
55     // Can a width x height rectangle fit in the free space represented by
56     // the skyline segments >= 'skylineIndex'? If so, return true and fill in
57     // 'y' with the y-location at which it fits (the x location is pulled from
58     // 'skylineIndex's segment.
59     bool rectangleFits(int skylineIndex, int width, int height, int* y) const;
60     // Update the skyline structure to include a width x height rect located
61     // at x,y.
62     void addSkylineLevel(int skylineIndex, int x, int y, int width, int height);
63 };
64 
65 } // End of namespace skgpu
66 
67 #endif
68