SkBicubicImageFilter.cpp revision 8b0e8ac5f582de80356019406e2975079bf0829d 
1/*
2 * Copyright 2013 The Android Open Source Project
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#include "SkBicubicImageFilter.h"
9#include "SkBitmap.h"
10#include "SkColorPriv.h"
11#include "SkReadBuffer.h"
12#include "SkWriteBuffer.h"
13#include "SkMatrix.h"
14#include "SkRect.h"
15#include "SkUnPreMultiply.h"
16
17#if SK_SUPPORT_GPU
18#include "effects/GrBicubicEffect.h"
19#include "GrContext.h"
20#include "GrTexture.h"
21#include "SkImageFilterUtils.h"
22#endif
23
24#define DS(x) SkDoubleToScalar(x)
25
26static const SkScalar gMitchellCoefficients[16] = {
27    DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
28    DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
29    DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
30    DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS(  7.0 / 18.0),
31};
32
33SkBicubicImageFilter::SkBicubicImageFilter(const SkSize& scale, const SkScalar coefficients[16], SkImageFilter* input)
34  : INHERITED(input),
35    fScale(scale) {
36    memcpy(fCoefficients, coefficients, sizeof(fCoefficients));
37}
38
39SkBicubicImageFilter* SkBicubicImageFilter::CreateMitchell(const SkSize& scale,
40                                                           SkImageFilter* input) {
41    return SkNEW_ARGS(SkBicubicImageFilter, (scale, gMitchellCoefficients, input));
42}
43
44SkBicubicImageFilter::SkBicubicImageFilter(SkReadBuffer& buffer)
45  : INHERITED(1, buffer) {
46    SkDEBUGCODE(bool success =) buffer.readScalarArray(fCoefficients, 16);
47    SkASSERT(success);
48    fScale.fWidth = buffer.readScalar();
49    fScale.fHeight = buffer.readScalar();
50    buffer.validate(SkScalarIsFinite(fScale.fWidth) &&
51                    SkScalarIsFinite(fScale.fHeight) &&
52                    (fScale.fWidth >= 0) &&
53                    (fScale.fHeight >= 0));
54}
55
56void SkBicubicImageFilter::flatten(SkWriteBuffer& buffer) const {
57    this->INHERITED::flatten(buffer);
58    buffer.writeScalarArray(fCoefficients, 16);
59    buffer.writeScalar(fScale.fWidth);
60    buffer.writeScalar(fScale.fHeight);
61}
62
63SkBicubicImageFilter::~SkBicubicImageFilter() {
64}
65
66inline SkPMColor cubicBlend(const SkScalar c[16], SkScalar t, SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
67    SkScalar t2 = t * t, t3 = t2 * t;
68    SkScalar cc[4];
69    // FIXME:  For the fractx case, this should be refactored out of this function.
70    cc[0] = c[0]  + SkScalarMul(c[1], t) + SkScalarMul(c[2], t2) + SkScalarMul(c[3], t3);
71    cc[1] = c[4]  + SkScalarMul(c[5], t) + SkScalarMul(c[6], t2) + SkScalarMul(c[7], t3);
72    cc[2] = c[8]  + SkScalarMul(c[9], t) + SkScalarMul(c[10], t2) + SkScalarMul(c[11], t3);
73    cc[3] = c[12] + SkScalarMul(c[13], t) + SkScalarMul(c[14], t2) + SkScalarMul(c[15], t3);
74    SkScalar a = SkScalarClampMax(SkScalarMul(cc[0], SkGetPackedA32(c0)) + SkScalarMul(cc[1], SkGetPackedA32(c1)) + SkScalarMul(cc[2], SkGetPackedA32(c2)) + SkScalarMul(cc[3], SkGetPackedA32(c3)), 255);
75    SkScalar r = SkScalarMul(cc[0], SkGetPackedR32(c0)) + SkScalarMul(cc[1], SkGetPackedR32(c1)) + SkScalarMul(cc[2], SkGetPackedR32(c2)) + SkScalarMul(cc[3], SkGetPackedR32(c3));
76    SkScalar g = SkScalarMul(cc[0], SkGetPackedG32(c0)) + SkScalarMul(cc[1], SkGetPackedG32(c1)) + SkScalarMul(cc[2], SkGetPackedG32(c2)) + SkScalarMul(cc[3], SkGetPackedG32(c3));
77    SkScalar b = SkScalarMul(cc[0], SkGetPackedB32(c0)) + SkScalarMul(cc[1], SkGetPackedB32(c1)) + SkScalarMul(cc[2], SkGetPackedB32(c2)) + SkScalarMul(cc[3], SkGetPackedB32(c3));
78    return SkPackARGB32(SkScalarRoundToInt(a),
79                        SkScalarRoundToInt(SkScalarClampMax(r, a)),
80                        SkScalarRoundToInt(SkScalarClampMax(g, a)),
81                        SkScalarRoundToInt(SkScalarClampMax(b, a)));
82}
83
84bool SkBicubicImageFilter::onFilterImage(Proxy* proxy,
85                                         const SkBitmap& source,
86                                         const SkMatrix& matrix,
87                                         SkBitmap* result,
88                                         SkIPoint* offset) {
89    SkBitmap src = source;
90    SkIPoint srcOffset = SkIPoint::Make(0, 0);
91    if (getInput(0) && !getInput(0)->filterImage(proxy, source, matrix, &src, &srcOffset)) {
92        return false;
93    }
94
95    if (src.config() != SkBitmap::kARGB_8888_Config) {
96        return false;
97    }
98
99    SkAutoLockPixels alp(src);
100    if (!src.getPixels()) {
101        return false;
102    }
103
104    SkRect dstRect = SkRect::MakeWH(SkScalarMul(SkIntToScalar(src.width()), fScale.fWidth),
105                                    SkScalarMul(SkIntToScalar(src.height()), fScale.fHeight));
106    SkIRect dstIRect;
107    dstRect.roundOut(&dstIRect);
108    if (dstIRect.isEmpty()) {
109        return false;
110    }
111    result->setConfig(src.config(), dstIRect.width(), dstIRect.height());
112    if (!result->allocPixels()) {
113        return false;
114    }
115
116    SkRect srcRect;
117    src.getBounds(&srcRect);
118    srcRect.offset(SkPoint::Make(SkIntToScalar(srcOffset.fX), SkIntToScalar(srcOffset.fY)));
119    SkMatrix inverse;
120    inverse.setRectToRect(dstRect, srcRect, SkMatrix::kFill_ScaleToFit);
121    inverse.postTranslate(-0.5f, -0.5f);
122
123    for (int y = dstIRect.fTop; y < dstIRect.fBottom; ++y) {
124        SkPMColor* dptr = result->getAddr32(dstIRect.fLeft, y);
125        for (int x = dstIRect.fLeft; x < dstIRect.fRight; ++x) {
126            SkPoint srcPt, dstPt = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
127            inverse.mapPoints(&srcPt, &dstPt, 1);
128            SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
129            SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
130            int sx = SkScalarFloorToInt(srcPt.fX);
131            int sy = SkScalarFloorToInt(srcPt.fY);
132            int x0 = SkClampMax(sx - 1, src.width() - 1);
133            int x1 = SkClampMax(sx    , src.width() - 1);
134            int x2 = SkClampMax(sx + 1, src.width() - 1);
135            int x3 = SkClampMax(sx + 2, src.width() - 1);
136            int y0 = SkClampMax(sy - 1, src.height() - 1);
137            int y1 = SkClampMax(sy    , src.height() - 1);
138            int y2 = SkClampMax(sy + 1, src.height() - 1);
139            int y3 = SkClampMax(sy + 2, src.height() - 1);
140            SkPMColor s00 = *src.getAddr32(x0, y0);
141            SkPMColor s10 = *src.getAddr32(x1, y0);
142            SkPMColor s20 = *src.getAddr32(x2, y0);
143            SkPMColor s30 = *src.getAddr32(x3, y0);
144            SkPMColor s0 = cubicBlend(fCoefficients, fractx, s00, s10, s20, s30);
145            SkPMColor s01 = *src.getAddr32(x0, y1);
146            SkPMColor s11 = *src.getAddr32(x1, y1);
147            SkPMColor s21 = *src.getAddr32(x2, y1);
148            SkPMColor s31 = *src.getAddr32(x3, y1);
149            SkPMColor s1 = cubicBlend(fCoefficients, fractx, s01, s11, s21, s31);
150            SkPMColor s02 = *src.getAddr32(x0, y2);
151            SkPMColor s12 = *src.getAddr32(x1, y2);
152            SkPMColor s22 = *src.getAddr32(x2, y2);
153            SkPMColor s32 = *src.getAddr32(x3, y2);
154            SkPMColor s2 = cubicBlend(fCoefficients, fractx, s02, s12, s22, s32);
155            SkPMColor s03 = *src.getAddr32(x0, y3);
156            SkPMColor s13 = *src.getAddr32(x1, y3);
157            SkPMColor s23 = *src.getAddr32(x2, y3);
158            SkPMColor s33 = *src.getAddr32(x3, y3);
159            SkPMColor s3 = cubicBlend(fCoefficients, fractx, s03, s13, s23, s33);
160            *dptr++ = cubicBlend(fCoefficients, fracty, s0, s1, s2, s3);
161        }
162    }
163    offset->fX = dstIRect.fLeft;
164    offset->fY = dstIRect.fTop;
165    return true;
166}
167
168///////////////////////////////////////////////////////////////////////////////
169
170#if SK_SUPPORT_GPU
171
172bool SkBicubicImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, const SkMatrix& ctm,
173                                          SkBitmap* result, SkIPoint* offset) {
174    SkBitmap srcBM;
175    if (!SkImageFilterUtils::GetInputResultGPU(getInput(0), proxy, src, ctm, &srcBM, offset)) {
176        return false;
177    }
178    GrTexture* srcTexture = srcBM.getTexture();
179    GrContext* context = srcTexture->getContext();
180
181    SkRect dstRect = SkRect::MakeWH(srcBM.width() * fScale.fWidth,
182                                    srcBM.height() * fScale.fHeight);
183
184    GrTextureDesc desc;
185    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
186    desc.fWidth = SkScalarCeilToInt(dstRect.width());
187    desc.fHeight = SkScalarCeilToInt(dstRect.height());
188    desc.fConfig = kSkia8888_GrPixelConfig;
189
190    GrAutoScratchTexture ast(context, desc);
191    SkAutoTUnref<GrTexture> dst(ast.detach());
192    if (!dst) {
193        return false;
194    }
195    GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
196    GrPaint paint;
197    paint.addColorEffect(GrBicubicEffect::Create(srcTexture, fCoefficients))->unref();
198    SkRect srcRect;
199    srcBM.getBounds(&srcRect);
200    context->drawRectToRect(paint, dstRect, srcRect);
201    return SkImageFilterUtils::WrapTexture(dst, desc.fWidth, desc.fHeight, result);
202}
203#endif
204
205///////////////////////////////////////////////////////////////////////////////
206