![@Override
protected void onDraw(Canvas canvas) {
// Clip with a shape
Path clip = getPath();
canvas.clipPath(clip);
// Draw the content
for (int i = 0; i < mLines,length; i++) {
TextLine line = mLines[i];
canvas.drawText(line.text,
line.x, line.y, mPaint);
}
}](https://image.slidesharecdn.com/103-20-20android-20graphics-20performance-131007130312-phpapp02/85/Google-I-O-2013-Android-Graphics-Performance-19-320.jpg)
Google I/O 2013 - Android Graphics Performance
- 4. &Chet Haase Romain Guy
- 5. Architecture
- 7. Save Cancel Maximize compatibility Include metadata
- 9. Include metadata Maximize compatibility CancelSave Order of drawing commands
- 10. Include metadata Maximize compatibility CancelSave 1. Re-ordering
- 13. Multi-threading
- 15. Drawing
- 19. @Override protected void onDraw(Canvas canvas) { // Clip with a shape Path clip = getPath(); canvas.clipPath(clip); // Draw the content for (int i = 0; i < mLines,length; i++) { TextLine line = mLines[i]; canvas.drawText(line.text, line.x, line.y, mPaint); } }
- 21. Overdraw
- 22. Overdraw
- 23. Overdraw
- 25. 0 3 6 9 12 15 Timeinms Frames Update display lists Process display lists Swap buffers
- 29. android:sdk $ cd platform-tools/ android:platform-tools $ ./systrace.py gfx view freq sched
- 31. import android.os.Trace; @Override public View getView(int pos, View view, ViewGroup parent) { Trace.beginSection("getView"); if (view == null) { view = createView(); } // Trace time spent binding data Trace.beginSection("bind"); bindView(pos, view); Trace.endSection(); Trace.endSection(); return view; }
- 32. android:sdk $ cd platform-tools/ android:platform-tools $ ./systrace.py -a com.example.myapp
- 33. Tips & Tricks 3
- 34. Overdraw demo
- 37. Off On
- 38. private void loadData() { // Load bitmap Bitmap b = getBitmap(); // Enable trilinear filtering b.setHasMipMap(true); }
- 40. Canvas layers
- 41. @Override protected void onDraw(Canvas canvas) { // Create a clipped layer canvas.save(); canvas.saveLayer(x, y, width, height, Canvas.CLIP_TO_LAYER_SAVE_FLAG); // Draw stuff canvas.drawBitmap(bugDroid, 0.0f, 0.0f, null); canvas.restore(); }
- 42. saveLayer()
- 45. @Override protected void onDraw(Canvas canvas) { // Create an unclipped layer canvas.save(); canvas.saveLayer(x, y, width, height, 0); // Draw stuff canvas.drawBitmap(bugDroid, 0.0f, 0.0f, null); canvas.restore(); }
- 46. saveLayer()
- 49. Using alpha with care
- 51. view.setAlpha(0.5f); View.ALPHA.set(view, 0.5f); ObjectAnimation.ofFloat(view, "alpha", 0.5f) view.animate().alpha(0.5f); view.setAnimation(new AlphaAnimation(1.0f, 0.5f));
- 52. view.setAlpha(0.5f); View.ALPHA.set(view, 0.5f); ObjectAnimation.ofFloat(view, "alpha", 0.5f) view.animate().alpha(0.5f); view.setAnimation(new AlphaAnimation(1.0f, 0.5f)); Canvas.saveLayerAlpha(l, t, r, b, 127, Canvas.CLIP_TO_LAYER_SAVE_FLAG); ==
- 57. lternatives
- 58. // Not this textView.setAlpha(alpha); // But this int newTextColor = (int) (0xFF * alpha) << 24 | baseTextColor & 0xFFFFFF; textView.setTextColor(newTextColor);
- 59. // Not this imageView.setAlpha(alpha); // But this imageView.setImageAlpha((int) (alpha * 255));
- 60. // Not this customView.setAlpha(alpha); // But this int alpha = (int) (255 * slider.getProgress() / 100.0f); paint.setAlpha(alpha); canvas.draw*(..., paint);
- 61. // Or use a layer view.setLayerType(View.LAYER_TYPE_HARDWARE, null); // Transient layer view.animate().alpha(0).withLayer();
- 62. // API level 16+ @Override public boolean hasOverlappingRendering() { // Don't lie to us! return false; }
- 64. @Override protected void onDraw(Canvas canvas) { // Get the dimensions of the Canvas int w = canvas.getWidth(); int h = canvas.getHeight(); canvas.drawRect(0, 0, w, h, mPaint); }
- 67. With hardware rendering 600x300 px (size of the View)
- 68. With hardware rendering With software rendering 600x300 px 1280x800 px (size of the View) (size of the window)
- 69. ✂ Clipping
- 70. @Override protected void onDraw(Canvas canvas) { // Keep the jellybeans canvas.clipRect(l, t, r, b); // Rotate the jar canvas.rotate(-30.0f, pX, pY); // Draw the jar canvas.drawBitmap(mJellyBeans, x, y, null); }
- 72. 1. Clip
- 73. 2. Rotate
- 74. 3. Draw
- 76. @Override protected void onDraw(Canvas canvas) { // Rotate the jar canvas.rotate(-30.0f, pX, pY); // Keep the jellybeans canvas.clipRect(l, t, r, b); // Draw the jar canvas.drawBitmap(mJellyBeans, x, y, null); }
- 78. 1. Rotate
- 79. 2. Clip
- 80. 3. Draw
- 82. Stencilbuffer
- 83. Stencilbuffer
- 86. @Override protected void onDraw(Canvas canvas) { // Query the current clip Rect clip = canvas.getClipBounds(); // ??? Log.d("I/O", "clip = " + clip); }
- 88. With hardware rendering 0, 0, 640, 400 (bounds of the View)
- 89. With hardware rendering With software rendering 0, 0, 640, 400 170,125, 470, 275 (bounds of the View) (bounds of the dirty rect)
- 92. saveLayer()
- 93. More info Parleys.com For Butter or Worse Google I/O 2012 Various Android GUI & performance talks Accelerated Android Rendering Google I/O 2011
- 94. More info Romain’s Tips & Tricks www.curious-creature.org Chet’s Tips & Tricks goo.gl/y9JZr Android Performance Case Study graphics-geek.blogspot.com
- 96. Developers