| /* |
| * 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 "../include/core/SkCanvas.h" |
| #include "../include/core/SkData.h" |
| #include "../include/core/SkSurface.h" |
| #include "../include/effects/SkGradientShader.h" |
| #include "../include/gpu/GrContext.h" |
| |
| // These headers are just handy for writing this example file. Nothing Skia specific. |
| #include <cstdlib> |
| #include <ctime> |
| #include <fstream> |
| #include <iostream> |
| #include <memory> |
| |
| // These setup_gl_context() are not meant to represent good form. |
| // They are just quick hacks to get us going. |
| #if defined(__APPLE__) |
| #include <OpenGL/OpenGL.h> |
| static bool setup_gl_context() { |
| CGLPixelFormatAttribute attributes[] = { (CGLPixelFormatAttribute)0 }; |
| CGLPixelFormatObj format; |
| GLint npix; |
| CGLChoosePixelFormat(attributes, &format, &npix); |
| CGLContextObj context; |
| CGLCreateContext(format, nullptr, &context); |
| CGLSetCurrentContext(context); |
| CGLReleasePixelFormat(format); |
| return true; |
| } |
| #else |
| static bool setup_gl_context() { |
| return false; |
| } |
| #endif |
| |
| // Most pointers returned by Skia are derived from SkRefCnt, |
| // meaning we need to call ->unref() on them when done rather than delete them. |
| template <typename T> std::shared_ptr<T> adopt(T* ptr) { |
| return std::shared_ptr<T>(ptr, [](T* p) { p->unref(); }); |
| } |
| |
| static std::shared_ptr<SkSurface> create_raster_surface(int w, int h) { |
| std::cout << "Using raster surface" << std::endl; |
| return adopt(SkSurface::MakeRasterN32Premul(w, h).release()); |
| } |
| |
| static std::shared_ptr<SkSurface> create_opengl_surface(int w, int h) { |
| std::cout << "Using opengl surface" << std::endl; |
| std::shared_ptr<GrContext> grContext = adopt(GrContext::Create(kOpenGL_GrBackend, 0)); |
| return adopt(SkSurface::MakeRenderTarget(grContext.get(), |
| SkBudgeted::kNo, |
| SkImageInfo::MakeN32Premul(w,h)).release()); |
| } |
| |
| int main(int, char**) { |
| bool gl_ok = setup_gl_context(); |
| srand((unsigned)time(nullptr)); |
| std::shared_ptr<SkSurface> surface = (gl_ok && rand() % 2) ? create_opengl_surface(320, 240) |
| : create_raster_surface(320, 240); |
| |
| // Create a left-to-right green-to-purple gradient shader. |
| SkPoint pts[] = { {0,0}, {320,240} }; |
| SkColor colors[] = { 0xFF00FF00, 0xFFFF00FF }; |
| // Our text will draw with this paint: size 24, antialiased, with the shader. |
| SkPaint paint; |
| paint.setTextSize(24); |
| paint.setAntiAlias(true); |
| paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkShader::kRepeat_TileMode)); |
| |
| // Draw to the surface via its SkCanvas. |
| SkCanvas* canvas = surface->getCanvas(); // We don't manage this pointer's lifetime. |
| static const char* msg = "Hello world!"; |
| canvas->clear(SK_ColorWHITE); |
| canvas->drawText(msg, strlen(msg), 90,120, paint); |
| |
| // Grab a snapshot of the surface as an immutable SkImage. |
| sk_sp<SkImage> image = surface->makeImageSnapshot(); |
| // Encode that image as a .png into a blob in memory. |
| std::shared_ptr<SkData> png = adopt(image->encode(SkEncodedImageFormat::kPNG, 100)); |
| |
| // This code is no longer Skia-specific. We just dump the .png to disk. Any way works. |
| static const char* path = "example.png"; |
| std::ofstream(path, std::ios::out | std::ios::binary) |
| .write((const char*)png->data(), png->size()); |
| std::cout << "Wrote " << path << std::endl; |
| |
| return 0; |
| } |