skia2/samplecode/SamplePathFinder.cpp

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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SampleCode.h"
#include "SkCanvas.h"
#include "SkCommandLineFlags.h"
#include "SkOSPath.h"
#include "SkPath.h"
#include "SkPicture.h"
#include "SkStream.h"
#include <stack>
DEFINE_string(pathfinderTrail, "", "List of keystrokes to execute upon loading a pathfinder.");
/**
* This is a simple utility designed to extract the paths from an SKP file and then isolate a single
* one of them. Use the 'x' and 'X' keys to guide a binary search:
*
* 'x': Throw out half the paths.
* 'X': Toggle which half gets tossed and which half is kept.
* 'Z': Back up one level.
* 'D': Dump the path.
*/
class PathFinderView : public SampleView, public SkCanvas {
public:
PathFinderView(const char name[] = nullptr)
: SkCanvas(4096, 4096, nullptr)
, fFilename(name) {
SkFILEStream stream(fFilename.c_str());
if (!stream.isValid()) {
SkDebugf("couldn't load picture at \"%s\"\n", fFilename.c_str());
return;
}
sk_sp<SkPicture> pic = SkPicture::MakeFromStream(&stream);
if (!pic) {
SkDebugf("couldn't load picture at \"%s\"\n", fFilename.c_str());
return;
}
pic->playback(this);
for (int i = 0; i < FLAGS_pathfinderTrail.count(); ++i) {
const char* key = FLAGS_pathfinderTrail[i];
while (*key) {
this->handleKeystroke(*key++);
}
}
}
~PathFinderView() override {}
private:
// Called through SkPicture::playback during construction.
void onDrawPath(const SkPath& path, const SkPaint& paint) override {
fPaths.push_back() = {path, paint, this->getTotalMatrix()};
}
// overrides from SkEventSink
bool onQuery(SkEvent* evt) override {
if (SampleCode::TitleQ(*evt)) {
SkString name("PATHFINDER:");
const char* basename = strrchr(fFilename.c_str(), SkOSPath::SEPARATOR);
name.append(basename ? basename+1: fFilename.c_str());
SampleCode::TitleR(evt, name.c_str());
return true;
}
SkUnichar key;
if (SampleCode::CharQ(*evt, &key)) {
if (this->handleKeystroke(key)) {
return true;
}
}
return this->INHERITED::onQuery(evt);
}
bool handleKeystroke(SkUnichar key) {
switch (key) {
case 'X':
if (!fTossedPaths.empty()) {
SkTSwap(fPaths, fTossedPaths);
if ('X' == fTrail.back()) {
fTrail.pop_back();
} else {
fTrail.push_back('X');
}
this->inval(nullptr);
}
return true;
case 'x':
if (fPaths.count() > 1) {
int midpt = (fPaths.count() + 1) / 2;
fPathHistory.emplace(fPaths, fTossedPaths);
fTossedPaths.reset(fPaths.begin() + midpt, fPaths.count() - midpt);
fPaths.resize_back(midpt);
fTrail.push_back('x');
this->inval(nullptr);
}
return true;
case 'Z': {
if (!fPathHistory.empty()) {
fPaths = fPathHistory.top().first;
fTossedPaths = fPathHistory.top().second;
fPathHistory.pop();
char ch;
do {
ch = fTrail.back();
fTrail.pop_back();
} while (ch != 'x');
this->inval(nullptr);
}
return true;
}
case 'D':
SkDebugf("SampleApp --pathfinder %s", fFilename.c_str());
if (!fTrail.empty()) {
SkDebugf(" --pathfinderTrail ", fFilename.c_str());
for (char ch : fTrail) {
SkDebugf("%c", ch);
}
}
SkDebugf("\n");
for (const FoundPath& foundPath : fPaths) {
foundPath.fPath.dump();
}
return true;
}
return false;
}
void onDrawContent(SkCanvas* canvas) override {
for (const FoundPath& path : fPaths) {
SkAutoCanvasRestore acr(canvas, true);
canvas->concat(path.fViewMatrix);
canvas->drawPath(path.fPath, path.fPaint);
}
}
struct FoundPath {
SkPath fPath;
SkPaint fPaint;
SkMatrix fViewMatrix;
};
SkString fFilename;
SkTArray<FoundPath> fPaths;
SkTArray<FoundPath> fTossedPaths;
SkTArray<char> fTrail;
std::stack<std::pair<SkTArray<FoundPath>, SkTArray<FoundPath>>> fPathHistory;
typedef SampleView INHERITED;
};
SampleView* CreateSamplePathFinderView(const char filename[]) {
return new PathFinderView(filename);
}