/*
Copyright (c) 2012 Emitrom LLC. All rights reserved.
For licensing questions, please contact us at licensing@emitrom.com
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package com.emitrom.lienzo.client.core.types;
import com.emitrom.lienzo.client.core.Context2D;
import com.emitrom.lienzo.client.core.util.ScratchCanvas;
import com.google.gwt.canvas.dom.client.CanvasPixelArray;
import com.google.gwt.core.client.JavaScriptObject;
/**
* Object that holds image data and a size.
*
* @see <a href="http://www.w3.org/TR/2dcontext/#imagedata">HTML Canvas 2D ImageData</a>
*/
public class ImageData extends JavaScriptObject
{
/**
* Number of colors at each location in the array.
*
* Because image data is stored as RGBA, this is 4.
*/
private static final int NUM_COLORS = 4;
/**
* Offsets for each color use RGBA ordering.
*/
public static final int OFFSET_RED = 0;
public static final int OFFSET_GREEN = 1;
public static final int OFFSET_BLUE = 2;
public static final int OFFSET_ALPHA = 3;
protected ImageData()
{
}
/**
* ImageData can't be cloned or deep-copied, it's an internal data structure and has some CRAZY crap in it, this is cheeeeeezy, but hey, it works, and it's portable!!!
*/
public final ImageData copy()
{
ScratchCanvas scratch = new ScratchCanvas(getWidth(), getHeight());
Context2D context = scratch.getContext();
context.putImageData(this, 0, 0);
return context.getImageData(0, 0, getWidth(), getHeight());
}
/**
* Returns the alpha value at position (x,y).
*
* @param x the x coordinate
* @param y the y coordinate
* @return the alpha value at position (x,y), or 0 if not in the image
* @see #setAlphaAt(int, int, int)
* @see #getColorAt(int, int, int)
*/
public final int getAlphaAt(int x, int y)
{
return getColorAt(x, y, OFFSET_ALPHA);
}
/**
* Returns the blue value at position (x,y).
*
* @param x the x coordinate
* @param y the y coordinate
* @return the blue value at position (x,y), or 0 if not in the image
* @see #setBlueAt(int, int, int)
* @see #getColorAt(int, int, int)
*/
public final int getBlueAt(int x, int y)
{
return getColorAt(x, y, OFFSET_BLUE);
}
/**
* Returns a canvas pixel array of size width * height * 4.
*
* @return a {@link CanvasPixelArray} object
*/
public final native CanvasPixelArray getData() /*-{
return this.data;
}-*/;
/**
* Returns the green value at position (x,y).
*
* @param x the x coordinate
* @param y the y coordinate
* @return the green value at position (x,y), or 0 if not in the image
* @see #setGreenAt(int, int, int)
* @see #getColorAt(int, int, int)
*/
public final int getGreenAt(int x, int y)
{
return getColorAt(x, y, OFFSET_GREEN);
}
/**
* Returns the height of this image data object.
*
* @return the image height as an int
*/
public final native int getHeight() /*-{
return this.height;
}-*/;
/**
* Returns the red value at position (x,y).
*
* @param x the x coordinate
* @param y the y coordinate
* @return the red value at position (x,y), or 0 if not in the image
* @see #setRedAt(int, int, int)
* @see #getColorAt(int, int, int)
*/
public final int getRedAt(int x, int y)
{
return getColorAt(x, y, OFFSET_RED);
}
/**
* Returns the width of this image data object.
*
* @return the image width as an int
*/
public final native int getWidth() /*-{
return this.width;
}-*/;
/**
* Sets the alpha value at position (x,y).
*
* @param alpha the alpha value
* @param x the x coordinate
* @param y the y coordinate
* @see #getAlphaAt(int, int)
* @see #getColorAt(int, int, int)
*/
public final void setAlphaAt(int alpha, int x, int y)
{
setColorAt(alpha, x, y, OFFSET_ALPHA);
}
/**
* Sets the blue value at position (x,y).
*
* @param blue the blue value
* @param x the x coordinate
* @param y the y coordinate
* @see #getBlueAt(int, int)
* @see #getColorAt(int, int, int)
*/
public final void setBlueAt(int blue, int x, int y)
{
setColorAt(blue, x, y, OFFSET_BLUE);
}
/**
* Sets the green value at position (x,y).
*
* @param green the green value
* @param x the x coordinate
* @param y the y coordinate
* @see #getGreenAt(int, int)
* @see #getColorAt(int, int, int)
*/
public final void setGreenAt(int green, int x, int y)
{
setColorAt(green, x, y, OFFSET_GREEN);
}
/**
* Sets the red value at position (x,y).
*
* @param red the red value
* @param x the x coordinate
* @param y the y coordinate
* @see #getRedAt(int, int)
* @see #getColorAt(int, int, int)
*/
public final void setRedAt(int red, int x, int y)
{
setColorAt(red, x, y, OFFSET_RED);
}
/**
* Returns the color value at position (x,y) with the specified offset.
*
* Colors are stored in RGBA format, where the offset determines the color
* channel (R, G, B, or A). The values are stored in row-major order. If the
* specified location is not in the image, 0 is returned.
*
* @param x the x coordinate
* @param y the y coordinate
* @param offset the color offset
* @return the color value at position (x,y), or 0 if not in the image
* @see #setColorAt(int, int, int, int)
*/
private native int getColorAt(int x, int y, int offset) /*-{
return this.data[@com.google.gwt.canvas.dom.client.ImageData::NUM_COLORS
* (x + y * this.width) + offset] || 0;
}-*/;
/**
* Sets the color value at position (x,y) with the specified offset.
*
* Colors are stored in RGBA format, where the offset determines the color
* (R, G, B, or A.) The values are stored in row-major order.
*
* @param color the color (in the range 0...255)
* @param x the x coordinate
* @param y the y coordinate
* @param offset the color offset
* @see #getColorAt(int, int, int)
*/
private native void setColorAt(int color, int x, int y, int offset) /*-{
this.data[@com.google.gwt.canvas.dom.client.ImageData::NUM_COLORS
* (x + y * this.width) + offset] = color;
}-*/;
}