SW backend for viewer on Windows

tools/viewer/sk_app/win/RasterWindowContext_win.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "WindowContextFactory_win.h"
+#include "../RasterWindowContext.h"
+#include "SkSurface.h"
+
+#include <Windows.h>
+
+using sk_app::RasterWindowContext;
+using sk_app::DisplayParams;
+
+namespace {
+
+class RasterWindowContext_win : public RasterWindowContext {
+public:
+    RasterWindowContext_win(HWND, const DisplayParams&);
+
+    sk_sp<SkSurface> getBackbufferSurface() override;
+    void swapBuffers() override;
+    bool isValid() override { return SkToBool(fWnd); }
+    void resize(int w, int h) override;
+    void setDisplayParams(const DisplayParams& params) override;
+
+protected:
+    SkAutoMalloc fSurfaceMemory;
+    sk_sp<SkSurface> fBackbufferSurface;
+    HWND fWnd;
+};
+
+RasterWindowContext_win::RasterWindowContext_win(HWND wnd, const DisplayParams& params)
+        : fWnd(wnd) {
+    fDisplayParams = params;
+    RECT rect;
+    GetWindowRect(wnd, &rect);
+    this->resize(rect.right - rect.left, rect.bottom - rect.top);
+}
+
+void RasterWindowContext_win::setDisplayParams(const DisplayParams& params) {
+    fDisplayParams = params;
+    RECT rect;
+    GetWindowRect(fWnd, &rect);
+    this->resize(rect.right - rect.left, rect.bottom - rect.top);
+}
+
+void RasterWindowContext_win::resize(int w, int h) {
+    fWidth = w;
+    fHeight = h;
+    fBackbufferSurface.reset();
+    const size_t bmpSize = sizeof(BITMAPINFOHEADER) + w * h * sizeof(uint32_t);
+    fSurfaceMemory.reset(bmpSize);
+    BITMAPINFO* bmpInfo = reinterpret_cast<BITMAPINFO*>(fSurfaceMemory.get());
+    ZeroMemory(bmpInfo, sizeof(BITMAPINFO));
+    bmpInfo->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
+    bmpInfo->bmiHeader.biWidth = w;
+    bmpInfo->bmiHeader.biHeight = -h; // negative means top-down bitmap. Skia draws top-down.
+    bmpInfo->bmiHeader.biPlanes = 1;
+    bmpInfo->bmiHeader.biBitCount = 32;
+    bmpInfo->bmiHeader.biCompression = BI_RGB;
+    void* pixels = bmpInfo->bmiColors;
+
+    SkImageInfo info = SkImageInfo::Make(w, h, fDisplayParams.fColorType, kPremul_SkAlphaType,
+                                         fDisplayParams.fColorSpace);
+    fBackbufferSurface = SkSurface::MakeRasterDirect(info, pixels, sizeof(uint32_t) * w);
+}
+
+sk_sp<SkSurface> RasterWindowContext_win::getBackbufferSurface() { return fBackbufferSurface; }
+
+void RasterWindowContext_win::swapBuffers() {
+    BITMAPINFO* bmpInfo = reinterpret_cast<BITMAPINFO*>(fSurfaceMemory.get());
+    HDC dc = GetDC(fWnd);
+    StretchDIBits(dc, 0, 0, fWidth, fHeight, 0, 0, fWidth, fHeight, bmpInfo->bmiColors, bmpInfo,
+                  DIB_RGB_COLORS, SRCCOPY);
+    ReleaseDC(fWnd, dc);
+}
+
+}  // anonymous namespace
+
+namespace sk_app {
+namespace window_context_factory {
+
+WindowContext* NewRasterForWin(HWND wnd, const DisplayParams& params) {
+    WindowContext* ctx = new RasterWindowContext_win(wnd, params);
+    if (!ctx->isValid()) {
+        delete ctx;
+        ctx = nullptr;
+    }
+    return ctx;
+}
+
+}  // namespace window_context_factory
+}  // namespace sk_app