/*
* Copyright (C) 2010 The Android Open Source Project
*
* 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 android.graphics;
import com.android.ide.common.rendering.api.LayoutLog;
import com.android.layoutlib.bridge.Bridge;
import com.android.layoutlib.bridge.impl.DelegateManager;
import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
import android.graphics.Shader.TileMode;
/**
* Delegate implementing the native methods of android.graphics.LinearGradient
*
* Through the layoutlib_create tool, the original native methods of LinearGradient have been
* replaced by calls to methods of the same name in this delegate class.
*
* This class behaves like the original native implementation, but in Java, keeping previously
* native data into its own objects and mapping them to int that are sent back and forth between
* it and the original LinearGradient class.
*
* Because this extends {@link Shader_Delegate}, there's no need to use a {@link DelegateManager},
* as all the Shader classes will be added to the manager owned by {@link Shader_Delegate}.
*
* @see Shader_Delegate
*
*/
public final class LinearGradient_Delegate extends Gradient_Delegate {
// ---- delegate data ----
private java.awt.Paint mJavaPaint;
// ---- Public Helper methods ----
@Override
public java.awt.Paint getJavaPaint() {
return mJavaPaint;
}
// ---- native methods ----
@LayoutlibDelegate
/*package*/ static long nativeCreate1(LinearGradient thisGradient,
float x0, float y0, float x1, float y1,
int colors[], float positions[], int tileMode) {
LinearGradient_Delegate newDelegate = new LinearGradient_Delegate(x0, y0, x1, y1,
colors, positions, Shader_Delegate.getTileMode(tileMode));
return sManager.addNewDelegate(newDelegate);
}
@LayoutlibDelegate
/*package*/ static long nativeCreate2(LinearGradient thisGradient,
float x0, float y0, float x1, float y1,
int color0, int color1, int tileMode) {
return nativeCreate1(thisGradient,
x0, y0, x1, y1, new int[] { color0, color1}, null /*positions*/,
tileMode);
}
// ---- Private delegate/helper methods ----
/**
* Create a shader that draws a linear gradient along a line.
*
* @param x0 The x-coordinate for the start of the gradient line
* @param y0 The y-coordinate for the start of the gradient line
* @param x1 The x-coordinate for the end of the gradient line
* @param y1 The y-coordinate for the end of the gradient line
* @param colors The colors to be distributed along the gradient line
* @param positions May be null. The relative positions [0..1] of each
* corresponding color in the colors array. If this is null, the
* the colors are distributed evenly along the gradient line.
* @param tile The Shader tiling mode
*/
private LinearGradient_Delegate(float x0, float y0, float x1, float y1,
int colors[], float positions[], TileMode tile) {
super(colors, positions);
mJavaPaint = new LinearGradientPaint(x0, y0, x1, y1, mColors, mPositions, tile);
}
// ---- Custom Java Paint ----
/**
* Linear Gradient (Java) Paint able to handle more than 2 points, as
* {@link java.awt.GradientPaint} only supports 2 points and does not support Android's tile
* modes.
*/
private class LinearGradientPaint extends GradientPaint {
private final float mX0;
private final float mY0;
private final float mDx;
private final float mDy;
private final float mDSize2;
public LinearGradientPaint(float x0, float y0, float x1, float y1, int colors[],
float positions[], TileMode tile) {
super(colors, positions, tile);
mX0 = x0;
mY0 = y0;
mDx = x1 - x0;
mDy = y1 - y0;
mDSize2 = mDx * mDx + mDy * mDy;
}
@Override
public java.awt.PaintContext createContext(
java.awt.image.ColorModel colorModel,
java.awt.Rectangle deviceBounds,
java.awt.geom.Rectangle2D userBounds,
java.awt.geom.AffineTransform xform,
java.awt.RenderingHints hints) {
precomputeGradientColors();
java.awt.geom.AffineTransform canvasMatrix;
try {
canvasMatrix = xform.createInverse();
} catch (java.awt.geom.NoninvertibleTransformException e) {
Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE,
"Unable to inverse matrix in LinearGradient", e, null /*data*/);
canvasMatrix = new java.awt.geom.AffineTransform();
}
java.awt.geom.AffineTransform localMatrix = getLocalMatrix();
try {
localMatrix = localMatrix.createInverse();
} catch (java.awt.geom.NoninvertibleTransformException e) {
Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE,
"Unable to inverse matrix in LinearGradient", e, null /*data*/);
localMatrix = new java.awt.geom.AffineTransform();
}
return new LinearGradientPaintContext(canvasMatrix, localMatrix, colorModel);
}
private class LinearGradientPaintContext implements java.awt.PaintContext {
private final java.awt.geom.AffineTransform mCanvasMatrix;
private final java.awt.geom.AffineTransform mLocalMatrix;
private final java.awt.image.ColorModel mColorModel;
private LinearGradientPaintContext(
java.awt.geom.AffineTransform canvasMatrix,
java.awt.geom.AffineTransform localMatrix,
java.awt.image.ColorModel colorModel) {
mCanvasMatrix = canvasMatrix;
mLocalMatrix = localMatrix;
mColorModel = colorModel;
}
@Override
public void dispose() {
}
@Override
public java.awt.image.ColorModel getColorModel() {
return mColorModel;
}
@Override
public java.awt.image.Raster getRaster(int x, int y, int w, int h) {
java.awt.image.BufferedImage image = new java.awt.image.BufferedImage(w, h,
java.awt.image.BufferedImage.TYPE_INT_ARGB);
int[] data = new int[w*h];
int index = 0;
float[] pt1 = new float[2];
float[] pt2 = new float[2];
for (int iy = 0 ; iy < h ; iy++) {
for (int ix = 0 ; ix < w ; ix++) {
// handle the canvas transform
pt1[0] = x + ix;
pt1[1] = y + iy;
mCanvasMatrix.transform(pt1, 0, pt2, 0, 1);
// handle the local matrix.
pt1[0] = pt2[0];
pt1[1] = pt2[1];
mLocalMatrix.transform(pt1, 0, pt2, 0, 1);
data[index++] = getColor(pt2[0], pt2[1]);
}
}
image.setRGB(0 /*startX*/, 0 /*startY*/, w, h, data, 0 /*offset*/, w /*scansize*/);
return image.getRaster();
}
}
/**
* Returns a color for an arbitrary point.
*/
private int getColor(float x, float y) {
float pos;
if (mDx == 0) {
pos = (y - mY0) / mDy;
} else if (mDy == 0) {
pos = (x - mX0) / mDx;
} else {
// find the x position on the gradient vector.
float _x = (mDx*mDy*(y-mY0) + mDy*mDy*mX0 + mDx*mDx*x) / mDSize2;
// from it get the position relative to the vector
pos = (_x - mX0) / mDx;
}
return getGradientColor(pos);
}
}
}
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