skia2/samplecode/SampleUnpremul.cpp

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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "sk_tool_utils.h"
#include "DecodeFile.h"
#include "Resources.h"
#include "SampleCode.h"
#include "SkBlurMask.h"
#include "SkBlurDrawLooper.h"
#include "SkCanvas.h"
#include "SkColorPriv.h"
#include "SkOSFile.h"
#include "SkOSPath.h"
#include "SkStream.h"
#include "SkString.h"
#include "SkSystemEventTypes.h"
#include "SkTypes.h"
#include "SkUtils.h"
#include "SkView.h"
/**
* Interprets c as an unpremultiplied color, and returns the
* premultiplied equivalent.
*/
static SkPMColor premultiply_unpmcolor(SkPMColor c) {
U8CPU a = SkGetPackedA32(c);
U8CPU r = SkGetPackedR32(c);
U8CPU g = SkGetPackedG32(c);
U8CPU b = SkGetPackedB32(c);
return SkPreMultiplyARGB(a, r, g, b);
}
class UnpremulView : public SampleView {
public:
UnpremulView(SkString res)
: fResPath(res)
, fPremul(true)
, fDecodeSucceeded(false) {
this->nextImage();
}
protected:
// overrides from SkEventSink
bool onQuery(SkEvent* evt) override {
if (SampleCode::TitleQ(*evt)) {
SampleCode::TitleR(evt, "unpremul");
return true;
}
SkUnichar uni;
if (SampleCode::CharQ(*evt, &uni)) {
char utf8[kMaxBytesInUTF8Sequence];
size_t size = SkUTF8_FromUnichar(uni, utf8);
// Only consider events for single char keys
if (1 == size) {
switch (utf8[0]) {
case fNextImageChar:
this->nextImage();
return true;
case fTogglePremulChar:
this->togglePremul();
return true;
default:
break;
}
}
}
return this->INHERITED::onQuery(evt);
}
void onDrawBackground(SkCanvas* canvas) override {
sk_tool_utils::draw_checkerboard(canvas, 0xFFCCCCCC, 0xFFFFFFFF, 12);
}
void onDrawContent(SkCanvas* canvas) override {
SkPaint paint;
paint.setAntiAlias(true);
paint.setTextSize(SkIntToScalar(24));
auto looper(
SkBlurDrawLooper::Make(SK_ColorBLUE, SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(2)),
0, 0));
paint.setLooper(looper);
SkScalar height = paint.getFontMetrics(nullptr);
if (!fDecodeSucceeded) {
SkString failure;
if (fResPath.size() == 0) {
failure.printf("resource path is required!");
} else {
failure.printf("Failed to decode %s", fCurrFile.c_str());
}
canvas->drawString(failure, 0, height, paint);
return;
}
// Name, size of the file, and whether or not it is premultiplied.
SkString header(SkOSPath::Basename(fCurrFile.c_str()));
header.appendf(" [%dx%d] %s", fBitmap.width(), fBitmap.height(),
(fPremul ? "premultiplied" : "unpremultiplied"));
canvas->drawString(header, 0, height, paint);
canvas->translate(0, height);
// Help messages
header.printf("Press '%c' to move to the next image.'", fNextImageChar);
canvas->drawString(header, 0, height, paint);
canvas->translate(0, height);
header.printf("Press '%c' to toggle premultiplied decode.", fTogglePremulChar);
canvas->drawString(header, 0, height, paint);
// Now draw the image itself.
canvas->translate(height * 2, height * 2);
if (!fPremul) {
// A premultiplied bitmap cannot currently be drawn.
// Copy it to a bitmap which can be drawn, converting
// to premultiplied:
SkBitmap bm;
bm.allocN32Pixels(fBitmap.width(), fBitmap.height());
for (int i = 0; i < fBitmap.width(); ++i) {
for (int j = 0; j < fBitmap.height(); ++j) {
*bm.getAddr32(i, j) = premultiply_unpmcolor(*fBitmap.getAddr32(i, j));
}
}
canvas->drawBitmap(bm, 0, 0);
} else {
canvas->drawBitmap(fBitmap, 0, 0);
}
}
private:
const SkString fResPath;
SkString fCurrFile;
bool fPremul;
bool fDecodeSucceeded;
SkBitmap fBitmap;
SkOSFile::Iter fFileIter;
static const char fNextImageChar = 'j';
static const char fTogglePremulChar = 'h';
void nextImage() {
if (fResPath.size() == 0) {
return;
}
SkString basename;
if (!fFileIter.next(&basename)) {
fFileIter.reset(fResPath.c_str());
if (!fFileIter.next(&basename)) {
// Perhaps this should draw some error message?
return;
}
}
fCurrFile = SkOSPath::Join(fResPath.c_str(), basename.c_str());
this->decodeCurrFile();
}
void decodeCurrFile() {
if (fCurrFile.size() == 0) {
fDecodeSucceeded = false;
return;
}
fDecodeSucceeded = decode_file(fCurrFile.c_str(), &fBitmap, kN32_SkColorType, !fPremul);
this->inval(nullptr);
}
void togglePremul() {
fPremul = !fPremul;
this->decodeCurrFile();
}
typedef SampleView INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
static SkView* MyFactory() {
return new UnpremulView(GetResourcePath());
}
static SkViewRegister reg(MyFactory);