1
2 /*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11 #include "GrRectanizer.h"
12 #include "GrTBSearch.h"
13
14 #define MIN_HEIGHT_POW2 2
15
16 class GrRectanizerFIFO : public GrRectanizer {
17 public:
GrRectanizerFIFO(int w,int h)18 GrRectanizerFIFO(int w, int h) : GrRectanizer(w, h) {
19 fNextStripY = 0;
20 fAreaSoFar = 0;
21 Gr_bzero(fRows, sizeof(fRows));
22 }
23
~GrRectanizerFIFO()24 virtual ~GrRectanizerFIFO() {
25 }
26
27 virtual bool addRect(int w, int h, GrIPoint16* loc);
28
percentFull() const29 virtual float percentFull() const {
30 return fAreaSoFar / ((float)this->width() * this->height());
31 }
32
stripToPurge(int height) const33 virtual int stripToPurge(int height) const { return -1; }
purgeStripAtY(int yCoord)34 virtual void purgeStripAtY(int yCoord) { }
35
36 ///////////////////////////////////////////////////////////////////////////
37
38 struct Row {
39 GrIPoint16 fLoc;
40 int fRowHeight;
41
canAddWidthGrRectanizerFIFO::Row42 bool canAddWidth(int width, int containerWidth) const {
43 return fLoc.fX + width <= containerWidth;
44 }
45 };
46
47 Row fRows[16];
48
HeightToRowIndex(int height)49 static int HeightToRowIndex(int height) {
50 GrAssert(height >= MIN_HEIGHT_POW2);
51 return 32 - Gr_clz(height - 1);
52 }
53
54 int fNextStripY;
55 int32_t fAreaSoFar;
56
canAddStrip(int height) const57 bool canAddStrip(int height) const {
58 return fNextStripY + height <= this->height();
59 }
60
initRow(Row * row,int rowHeight)61 void initRow(Row* row, int rowHeight) {
62 row->fLoc.set(0, fNextStripY);
63 row->fRowHeight = rowHeight;
64 fNextStripY += rowHeight;
65 }
66 };
67
addRect(int width,int height,GrIPoint16 * loc)68 bool GrRectanizerFIFO::addRect(int width, int height, GrIPoint16* loc) {
69 if ((unsigned)width > (unsigned)this->width() ||
70 (unsigned)height > (unsigned)this->height()) {
71 return false;
72 }
73
74 int32_t area = width * height;
75
76 /*
77 We use bsearch, but there may be more than one row with the same height,
78 so we actually search for height-1, which can only be a pow2 itself if
79 height == 2. Thus we set a minimum height.
80 */
81 height = GrNextPow2(height);
82 if (height < MIN_HEIGHT_POW2) {
83 height = MIN_HEIGHT_POW2;
84 }
85
86 Row* row = &fRows[HeightToRowIndex(height)];
87 GrAssert(row->fRowHeight == 0 || row->fRowHeight == height);
88
89 if (0 == row->fRowHeight) {
90 if (!this->canAddStrip(height)) {
91 return false;
92 }
93 this->initRow(row, height);
94 } else {
95 if (!row->canAddWidth(width, this->width())) {
96 if (!this->canAddStrip(height)) {
97 return false;
98 }
99 // that row is now "full", so retarget our Row record for
100 // another one
101 this->initRow(row, height);
102 }
103 }
104
105 GrAssert(row->fRowHeight == height);
106 GrAssert(row->canAddWidth(width, this->width()));
107 *loc = row->fLoc;
108 row->fLoc.fX += width;
109
110 GrAssert(row->fLoc.fX <= this->width());
111 GrAssert(row->fLoc.fY <= this->height());
112 GrAssert(fNextStripY <= this->height());
113 fAreaSoFar += area;
114 return true;
115 }
116
117 ///////////////////////////////////////////////////////////////////////////////
118
Factory(int width,int height)119 GrRectanizer* GrRectanizer::Factory(int width, int height) {
120 return SkNEW_ARGS(GrRectanizerFIFO, (width, height));
121 }
122