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/*
* Copyright 2009, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// This file contains the declaration for the Canvas class.
#ifndef O3D_CORE_CROSS_CANVAS_H_
#define O3D_CORE_CROSS_CANVAS_H_
#include <vector>
#include "core/cross/param_object.h"
#include "core/cross/param.h"
#include "core/cross/texture.h"
#include "third_party/skia/files/include/core/SkBitmap.h"
#include "third_party/skia/files/include/core/SkCanvas.h"
namespace o3d {
class CanvasPaint;
// The Canvas class provides an API for drawing text and 2D primitives onto
// a 2D bitmap surface whose contents can be transfered to a compatible
// Texture2D object via the CopyToTexture() method. Each Canvas object
// maintains a stack of 2D transformation matrices which allow fine control over
// the placement of drawable elements. Both geometry and drawing coordinates
// provided to every draw call are transformed by the concatenation of
// all matrices in the stack.
class Canvas : public ParamObject {
public:
typedef SmartPointer<Canvas> Ref;
virtual ~Canvas();
// Sets the size of the bitmap surface this Canvas object will use.
bool SetSize(int width, int height);
// Initializes the bitmap's pixels with the specified color.
// Parameters:
// red: Red color value (between 0 and 1.0)
// green: Green color value (between 0 and 1.0)
// blue: Blue color value (between 0 and 1.0)
// alpha: Transparency value (0 = transparent, 1 = opaque)
void Clear(float red, float green, float blue, float alpha);
// Draws a rectangle using the specified coordinates. The rectangle will be
// filled based on the color and shader of the specified paint.
// Parameters:
// left The left side of the rectangle to be drawn
// top The top side of the rectangle to be drawn
// right The right side of the rectangle to be drawn
// bottom The bottom side of the rectangle to be drawn
// paint The CanvasPaint object used to draw the rectangle.
void DrawRect(float left,
float top,
float right,
float bottom,
CanvasPaint* paint);
// Draws the text, with origin at (x,y), using the specified paint. The origin
// is interpreted based on the textAlign property in the paint.
// Parameters:
// text: String of text to be drawn
// x: The x coordinate for the text origin
// y: The y coordinate for the text origin
// paint: The CanvasPaint object that specifies the text style, size, etc
void DrawText(const String& text, float x, float y, CanvasPaint* paint);
// Draws the text with its baseline along the
// specified path. The paint's textAlign property determines where along the
// path to start the text. The path must contain at least two positions.
// Parameters:
// text: String of text to be drawn
// positions: An array of x,y positions making up the path.
// horizonal_offset: The distance along the path to add to the text starting
// position.
// vertical_offset: The distance above(-) or below(+) the path to position
// the text.
// paint: The CanvasPaint object that specifies the text style, size, etc.
void DrawTextOnPath(const String& text,
std::vector<Float2> positions,
float horizontal_offset,
float vertical_offset,
CanvasPaint* paint);
// Draws the contents of the specified texture onto the canvas surface.
// The bottom left corner of the bitmap will be at (x, y) and transformed by
// the current matrix.
// Parameters:
// texture: Pointer to Texture2D object where the bitmap is extracted from
// left: The position of the left side of the bitmap.
// bottom: The position of the bottom side of the bitmap.
void DrawBitmap(Texture2D* texture,
float left,
float bottom);
// This call saves the current matrix information, and pushes a copy onto a
// private stack. Subsequent calls to translate, scale, rotate, all operate on
// this copy. When the balancing call to RestoreState() is made, this copy is
// deleted and the previous matrix is restored.
void SaveMatrix() { sk_canvas_.save(); }
// This call balances a previous call to SaveMatrix(), and is used to remove
// all modifications to the matrix since the last SaveMatrix call.
void RestoreMatrix() { sk_canvas_.restore(); }
// Preconcats the current canvas matrix with the specified rotation.
// Parameters:
// degrees: The amount to rotate, in degrees
void Rotate(float degrees);
// Preconcats the current canvas matrix with the specified scale.
// Parameters:
// sx: The amount to scale in x
// sy: The amount to scale in y
void Scale(float sx, float sy);
// Preconcats the current canvas matrix with the specified translation.
// Parameters:
// dx: The amount to translate in x
// dy: The amount to translate in y
void Translate(float dx, float dy);
// Copies the contents of the Canvas bitmap to a Texture2D object. The
// texture object must have the same size as the canvas and a ARGB8 or XRGB8
// format. All mip levels of the the texture will be filled.
// Parameters:
// texture_2d: The texture object to copy the bitmap to.
bool CopyToTexture(Texture2D* texture_2d);
// Returns the width of the canvas bitmap.
int width() { return width_; }
// Returns the height of the canvas bitmap.
int height() { return height_; }
protected:
explicit Canvas(ServiceLocator* service_locator);
private:
friend class IClassManager;
static ObjectBase::Ref Create(ServiceLocator* service_locator);
// Local area in memory to perform drawing operations.
SkBitmap sk_bitmap_;
SkCanvas sk_canvas_;
// bitmap width and height.
int width_;
int height_;
O3D_DECL_CLASS(Canvas, ParamObject)
DISALLOW_COPY_AND_ASSIGN(Canvas);
};
} // namespace o3d
#endif // O3D_CORE_CROSS_CANVAS_H_
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