skia2/example/HelloWorld.cpp

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/*
* Copyright 2015 Google Inc.
*
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
*/
#include "HelloWorld.h"
#include "gl/GrGLInterface.h"
#include "SkApplication.h"
#include "SkCanvas.h"
#include "SkGradientShader.h"
#include "SkGraphics.h"
#include "SkGr.h"
void application_init() {
SkGraphics::Init();
SkEvent::Init();
}
void application_term() {
SkEvent::Term();
}
HelloWorldWindow::HelloWorldWindow(void* hwnd)
: INHERITED(hwnd) {
fType = kGPU_DeviceType;
fRenderTarget = NULL;
fRotationAngle = 0;
this->setTitle();
this->setUpBackend();
}
HelloWorldWindow::~HelloWorldWindow() {
tearDownBackend();
}
void HelloWorldWindow::tearDownBackend() {
SkSafeUnref(fContext);
fContext = NULL;
SkSafeUnref(fInterface);
fInterface = NULL;
SkSafeUnref(fRenderTarget);
fRenderTarget = NULL;
INHERITED::detach();
}
void HelloWorldWindow::setTitle() {
SkString title("Hello World ");
title.appendf(fType == kRaster_DeviceType ? "raster" : "opengl");
INHERITED::setTitle(title.c_str());
}
bool HelloWorldWindow::setUpBackend() {
this->setColorType(kRGBA_8888_SkColorType);
this->setVisibleP(true);
this->setClipToBounds(false);
bool result = attach(kNativeGL_BackEndType, 0 /*msaa*/, &fAttachmentInfo);
if (false == result) {
SkDebugf("Not possible to create backend.\n");
detach();
return false;
}
fInterface = GrGLCreateNativeInterface();
SkASSERT(NULL != fInterface);
fContext = GrContext::Create(kOpenGL_GrBackend, (GrBackendContext)fInterface);
SkASSERT(NULL != fContext);
this->setUpRenderTarget();
return true;
}
void HelloWorldWindow::setUpRenderTarget() {
SkSafeUnref(fRenderTarget);
fRenderTarget = this->renderTarget(fAttachmentInfo, fInterface, fContext);
}
void HelloWorldWindow::drawContents(SkCanvas* canvas) {
// Clear background
canvas->drawColor(SK_ColorWHITE);
SkPaint paint;
paint.setColor(SK_ColorRED);
// Draw a rectangle with red paint
SkRect rect = {
10, 10,
128, 128
};
canvas->drawRect(rect, paint);
// Set up a linear gradient and draw a circle
{
SkPoint linearPoints[] = {
{0, 0},
{300, 300}
};
SkColor linearColors[] = {SK_ColorGREEN, SK_ColorBLACK};
SkShader* shader = SkGradientShader::CreateLinear(
linearPoints, linearColors, NULL, 2,
SkShader::kMirror_TileMode);
SkAutoUnref shader_deleter(shader);
paint.setShader(shader);
paint.setFlags(SkPaint::kAntiAlias_Flag);
canvas->drawCircle(200, 200, 64, paint);
// Detach shader
paint.setShader(NULL);
}
// Draw a message with a nice black paint.
paint.setFlags(
SkPaint::kAntiAlias_Flag |
SkPaint::kSubpixelText_Flag | // ... avoid waggly text when rotating.
SkPaint::kUnderlineText_Flag);
paint.setColor(SK_ColorBLACK);
paint.setTextSize(20);
canvas->save();
static const char message[] = "Hello World";
// Translate and rotate
canvas->translate(300, 300);
fRotationAngle += 0.2f;
if (fRotationAngle > 360) {
fRotationAngle -= 360;
}
canvas->rotate(fRotationAngle);
// Draw the text:
canvas->drawText(message, strlen(message), 0, 0, paint);
canvas->restore();
}
void HelloWorldWindow::draw(SkCanvas* canvas) {
drawContents(canvas);
// in case we have queued drawing calls
fContext->flush();
// Invalidate the window to force a redraw. Poor man's animation mechanism.
this->inval(NULL);
if (kRaster_DeviceType == fType) {
// need to send the raster bits to the (gpu) window
SkImage* snap = fSurface->newImageSnapshot();
size_t rowBytes;
SkImageInfo info;
const void* pixels = snap->peekPixels(&info, &rowBytes);
fRenderTarget->writePixels(0, 0, snap->width(), snap->height(),
SkImageInfo2GrPixelConfig(info.colorType(),
info.alphaType(),
info.profileType()),
pixels,
rowBytes,
GrContext::kFlushWrites_PixelOp);
SkSafeUnref(snap);
}
INHERITED::present();
}
void HelloWorldWindow::onSizeChange() {
setUpRenderTarget();
}
bool HelloWorldWindow::onHandleChar(SkUnichar unichar) {
if (' ' == unichar) {
fType = fType == kRaster_DeviceType ? kGPU_DeviceType: kRaster_DeviceType;
tearDownBackend();
setUpBackend();
this->setTitle();
this->inval(NULL);
}
return true;
}
SkOSWindow* create_sk_window(void* hwnd, int , char** ) {
return new HelloWorldWindow(hwnd);
}