content: /*
   * 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 java.awt.image.DataBufferInt;
  import java.awt.image.Raster;
  import java.awt.image.SampleModel;
  
  /**
   * Delegate implementing the native methods of android.graphics.SweepGradient
   *
   * Through the layoutlib_create tool, the original native methods of SweepGradient 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 SweepGradient 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 class SweepGradient_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 nativeCreate(long matrix, float x, float y, long[] colors,
              float[] positions, long colorSpaceHandle) {
          SweepGradient_Delegate newDelegate = new SweepGradient_Delegate(matrix, x, y, colors,
                  positions);
          return sManager.addNewDelegate(newDelegate);
      }
  
      // ---- Private delegate/helper methods ----
  
      /**
       * A subclass of Shader that draws a sweep gradient around a center point.
       *
       * @param nativeMatrix reference to the shader's native transformation matrix
       * @param cx       The x-coordinate of the center
       * @param cy       The y-coordinate of the center
       * @param colors   The colors to be distributed between around the center.
       *                 There must be at least 2 colors in the array.
       * @param positions May be NULL. The relative position of
       *                 each corresponding color in the colors array, beginning
       *                 with 0 and ending with 1.0. If the values are not
       *                 monotonic, the drawing may produce unexpected results.
       *                 If positions is NULL, then the colors are automatically
       *                 spaced evenly.
       */
      private SweepGradient_Delegate(long nativeMatrix, float cx, float cy,
              long[] colors, float[] positions) {
          super(nativeMatrix, colors, positions);
          mJavaPaint = new SweepGradientPaint(cx, cy, mColors, mPositions);
      }
  
      private class SweepGradientPaint extends GradientPaint {
  
          private final float mCx;
          private final float mCy;
  
          public SweepGradientPaint(float cx, float cy, int[] colors,
                  float[] positions) {
              super(colors, positions, null /*tileMode*/);
              mCx = cx;
              mCy = cy;
          }
  
          @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 SweepGradient", 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 SweepGradient", e, null /*data*/);
                  localMatrix = new java.awt.geom.AffineTransform();
              }
  
              return new SweepGradientPaintContext(canvasMatrix, localMatrix, colorModel);
          }
  
          private class SweepGradientPaintContext 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;
  
              public SweepGradientPaintContext(
                      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) {
  
                  int[] data = new int[w*h];
  
                  // compute angle from each point to the center, and figure out the distance from
                  // it.
                  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] - mCx;
                          pt1[1] = pt2[1] - mCy;
                          mLocalMatrix.transform(pt1, 0, pt2, 0, 1);
  
                          float dx = pt2[0];
                          float dy = pt2[1];
  
                          float angle;
                          if (dx == 0) {
                              angle = (float) (dy < 0 ? 3 * Math.PI / 2 : Math.PI / 2);
                          } else if (dy == 0) {
                              angle = (float) (dx < 0 ? Math.PI : 0);
                          } else {
                              angle = (float) Math.atan(dy / dx);
                              if (dx > 0) {
                                  if (dy < 0) {
                                      angle += Math.PI * 2;
                                  }
                              } else {
                                  angle += Math.PI;
                              }
                          }
  
                          // convert to 0-1. value and get color
                          data[index++] = getGradientColor((float) (angle / (2 * Math.PI)));
                      }
                  }
  
                  DataBufferInt dataBuffer = new DataBufferInt(data, data.length);
                  SampleModel colorModel = mColorModel.createCompatibleSampleModel(w, h);
                  return Raster.createWritableRaster(colorModel, dataBuffer, null);
              }
  
          }
      }
  }
  