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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 CanvasShader class.
#ifndef O3D_CORE_CROSS_CANVAS_SHADER_H_
#define O3D_CORE_CROSS_CANVAS_SHADER_H_
#include <vector>
#include "core/cross/param_object.h"
#include "core/cross/param.h"
#include "SkColor.h"
#include "SkPoint.h"
class SkShader;
namespace o3d {
// This is the base class for 2D gradient shaders that can be applied to a
// CanvasPaint. The shaders affect both text and primitive drawing in the
// canvas.
class CanvasShader : public ParamObject {
public:
enum TileMode {
CLAMP, /* copy the edge color if the shader draws outside of its bounds */
REPEAT, /* repeat horizontally and vertically outside its bounds */
MIRROR /* same, alternating mirror images */
};
typedef SmartPointer<CanvasShader> Ref;
explicit CanvasShader(ServiceLocator* service_locator);
virtual ~CanvasShader();
// Returns a pointer to the native (SKIA) shader object.
SkShader* GetNativeShader();
protected:
// Creates a new native (SKIA) shader object using the parameter values
// stored in the object.
virtual SkShader* MakeNativeShader() = 0;
SkShader* native_shader_;
bool needs_update_;
private:
O3D_DECL_CLASS(CanvasShader, ParamObject)
DISALLOW_COPY_AND_ASSIGN(CanvasShader);
};
// A shader that generates a linear gradient between two specified points.
// Two or more colors need to be specified for the gradient.
class CanvasLinearGradient : public CanvasShader {
public:
typedef SmartPointer<CanvasLinearGradient> Ref;
virtual ~CanvasLinearGradient();
// Sets the start point of the gradient.
void set_start_point(Float2 start_point) {
start_point_ = start_point;
}
// Returns the start point of the gradient.
Float2 start_point() {
return start_point_;
}
// Sets the end point of the gradient.
void set_end_point(Float2 end_point) {
end_point_ = end_point;
}
// Returns the end point of the gradient.
Float2 end_point() {
return end_point_;
}
// Sets the relative positions corresponding to the colors in the color array.
// If the positions list is empty then the colors will be spread evenly.
// Otherwise, position values should start with 0 and end with 1.0 and their
// count should be equal to the length of the colors_ array.
void set_positions(std::vector<float> positions) {
positions_ = positions;
needs_update_ = true;
}
std::vector<float> positions() {
return positions_;
}
// Sets the array of colors used by the gradient.
void set_colors(std::vector<Float4> colors) {
colors_ = colors;
needs_update_ = true;
}
// Returns the color array.
std::vector<Float4> colors() {
return colors_;
}
// Sets the tiling mode for the gradient which specifies how the shader
// repeats for values beyond the start and end points.
void set_tile_mode(CanvasShader::TileMode tile_mode) {
tile_mode_ = tile_mode;
needs_update_ = true;
}
// Returns the tile mode.
TileMode tile_mode() { return tile_mode_; }
protected:
explicit CanvasLinearGradient(ServiceLocator* service_locator);
virtual SkShader* MakeNativeShader();
private:
friend class IClassManager;
static ObjectBase::Ref Create(ServiceLocator* service_locator);
// Start and end points for the gradient.
Float2 start_point_;
Float2 end_point_;
// Array of colors.
std::vector<Float4> colors_;
// Array of positions corresponding to colors.
std::vector<float> positions_;
CanvasShader::TileMode tile_mode_;
O3D_DECL_CLASS(CanvasLinearGradient, CanvasShader)
DISALLOW_COPY_AND_ASSIGN(CanvasLinearGradient);
};
} // namespace o3d
#endif // O3D_CORE_CROSS_CANVAS_SHADER_H_
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