michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.toolbar;
michael@0: 
michael@0: import android.graphics.Bitmap;
michael@0: import android.graphics.Canvas;
michael@0: import android.graphics.Paint;
michael@0: import android.graphics.Path;
michael@0: import android.graphics.PorterDuff.Mode;
michael@0: import android.graphics.PorterDuffXfermode;
michael@0: import android.graphics.Shader;
michael@0: import android.os.Build;
michael@0: 
michael@0: class CanvasDelegate {
michael@0:     Paint mPaint;
michael@0:     PorterDuffXfermode mMode;
michael@0:     DrawManager mDrawManager;
michael@0: 
michael@0:     // DrawManager would do a default draw of the background.
michael@0:     static interface DrawManager {
michael@0:         public void defaultDraw(Canvas cavas);
michael@0:     }
michael@0: 
michael@0:     CanvasDelegate(DrawManager drawManager, Mode mode) {
michael@0:         mDrawManager = drawManager;
michael@0: 
michael@0:         // DST_IN masks, DST_OUT clips.
michael@0:         mMode = new PorterDuffXfermode(mode);
michael@0: 
michael@0:         mPaint = new Paint();
michael@0:         mPaint.setAntiAlias(true);
michael@0:         mPaint.setColor(0xFFFF0000);
michael@0:         mPaint.setStrokeWidth(0.0f);
michael@0:     }
michael@0: 
michael@0:     void draw(Canvas canvas, Path path, int width, int height) {
michael@0:         // Save the canvas. All PorterDuff operations should be done in a offscreen bitmap.
michael@0:         int count = canvas.saveLayer(0, 0, width, height, null,
michael@0:                                      Canvas.MATRIX_SAVE_FLAG |
michael@0:                                      Canvas.CLIP_SAVE_FLAG |
michael@0:                                      Canvas.HAS_ALPHA_LAYER_SAVE_FLAG |
michael@0:                                      Canvas.FULL_COLOR_LAYER_SAVE_FLAG |
michael@0:                                      Canvas.CLIP_TO_LAYER_SAVE_FLAG);
michael@0: 
michael@0:         // Do a default draw.
michael@0:         mDrawManager.defaultDraw(canvas);
michael@0: 
michael@0:         if (path != null && !path.isEmpty()) {
michael@0:             // ICS added double-buffering, which made it easier for drawing the Path directly over the DST.
michael@0:             // In pre-ICS, drawPath() doesn't seem to use ARGB_8888 mode for performance, hence transparency is not preserved.
michael@0:             if (Build.VERSION.SDK_INT >= 14) {
michael@0:                 mPaint.setXfermode(mMode);
michael@0:                 canvas.drawPath(path, mPaint);
michael@0:             } else {
michael@0:                 // Allocate a bitmap and draw the masking/clipping path.
michael@0:                 Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
michael@0:                 (new Canvas(bitmap)).drawPath(path, mPaint);
michael@0: 
michael@0:                 mPaint.setXfermode(mMode);
michael@0:                 canvas.drawBitmap(bitmap, 0, 0, mPaint);
michael@0:                 bitmap.recycle();
michael@0: 
michael@0:                 mPaint.setXfermode(null);
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // Restore the canvas.
michael@0:         canvas.restoreToCount(count);
michael@0:     }
michael@0: 
michael@0:     void setShader(Shader shader) {
michael@0:         mPaint.setShader(shader);
michael@0:     }
michael@0: }