rainmeter-studio/Common/Gfx/Canvas.h

114 lines
4.2 KiB
C++

/*
Copyright (C) 2013 Birunthan Mohanathas
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef RM_GFX_CANVAS_H_
#define RM_GFX_CANVAS_H_
#include "FontCollection.h"
#include "TextFormat.h"
namespace Gfx {
enum class Renderer
{
GDIP,
D2D,
// Attempts to use D2D. If D2D is not available, fallbacks to use GDI+.
PreferD2D
};
// Provides methods for drawing text, bitmaps, etc.
class __declspec(novtable) Canvas
{
public:
virtual ~Canvas();
Canvas(const Canvas& other) = delete;
// Creates the canvas using the specified rendering engine. May return nullptr.
static Canvas* Create(Renderer renderer);
int GetW() const { return m_W; }
int GetH() const { return m_H; }
void SetAccurateText(bool option) { m_AccurateText = option; }
// Resize the draw area of the Canvas. This function must not be called if BeginDraw() has been
// called and has not yet been matched by a correspoding call to EndDraw.
virtual void Resize(int w, int h);
// BeginDraw() must be matched by a corresponding call to EndDraw(). Drawing functions must be
// be called only between BeginDraw() and EndDraw().
virtual bool BeginDraw() = 0;
virtual void EndDraw() = 0;
// Allows the use of Gdiplus::Graphics to perform drawing. Must be called between BeginDraw()
// and EndDraw(). BeginGdiplusGraphicsContext() must be matched by a corresponding call to
// EndGdiplusGraphicsContext(). While in the Gdiplus context, non-const member functions of
// this class must not be called.
virtual Gdiplus::Graphics& BeginGdiplusContext() = 0;
virtual void EndGdiplusContext() = 0;
// Returns a read-only DC. Must be called between BeginDraw() and EndDraw(). GetDC() must be
// matched by a corresponding call to ReleaseDC(). While in the Gdiplus context, non-const
// member functions of this class must not be called.
virtual HDC GetDC() = 0;
virtual void ReleaseDC(HDC dc) = 0;
// The Create* functions allocate objects specific to this Canvas object.
virtual FontCollection* CreateFontCollection() = 0;
virtual TextFormat* CreateTextFormat() = 0;
virtual bool IsTransparentPixel(int x, int y) = 0;
virtual void SetTransform(const Gdiplus::Matrix& matrix) = 0;
virtual void ResetTransform() = 0;
virtual void RotateTransform(float angle, float x, float y, float dx, float dy) = 0;
virtual void SetAntiAliasing(bool enable) = 0;
virtual void SetTextAntiAliasing(bool enable) = 0;
virtual void Clear(const Gdiplus::Color& color = Gdiplus::Color(0, 0, 0, 0)) = 0;
virtual void DrawTextW(const WCHAR* str, UINT strLen, const TextFormat& format, Gdiplus::RectF& rect, const Gdiplus::SolidBrush& brush) = 0;
virtual bool MeasureTextW(const WCHAR* str, UINT strLen, const TextFormat& format, Gdiplus::RectF& rect) = 0;
virtual bool MeasureTextLinesW(const WCHAR* str, UINT strLen, const TextFormat& format, Gdiplus::RectF& rect, UINT& lines) = 0;
virtual void DrawBitmap(Gdiplus::Bitmap* bitmap, const Gdiplus::Rect& dstRect, const Gdiplus::Rect& srcRect) = 0;
virtual void FillRectangle(Gdiplus::Rect& rect, const Gdiplus::SolidBrush& brush) = 0;
protected:
Canvas();
int m_W;
int m_H;
// GDI+, by default, includes padding around the string and also has a larger character spacing
// compared to DirectWrite. In order to minimize diffeences between the text renderers,
// an option is provided to enable accurate (typographic) text rendering. If set to |true|,
// it is expected that there is no padding around the text and that the output is similar to
// the default DirectWrite output. Otherwise, the expected result should be similar to that of
// non-typographic GDI+.
bool m_AccurateText;
};
} // namespace Gfx
#endif