LCL-CustomDrawn: Buffers the canvas bitmap in Android which greatly diminishes the garbage collector activity and speeds drawing. Also adds a new callback routine to select forms of the project which should have the background drawing painting skipped to speed up drawing

git-svn-id: trunk@36700 -

examples/androidlcl/android/src/com/pascal/lcltest/LCLActivity.java

@@ -46,7 +46,7 @@ public class LCLActivity extends Activity implements SensorEventListener, Locati
         .newEditable("Placeholder");
       }
       return _editable;
-    } This crashes in HTC */
+    } This crashes in HTC!!! */
 
     // This method sends a text to be added at the current cursor position
     @Override public boolean commitText(CharSequence text, int newCursorPosition)
@@ -97,6 +97,8 @@ public class LCLActivity extends Activity implements SensorEventListener, Locati
   // -------------------------------------------
   private class LCLSurface extends View
   {
+    private Bitmap canvasbitmap; // This is the buffered canvas bitmap, which is reused until the canvas size changes
+
     public LCLSurface(Context context)
     {
       super(context);
@@ -121,16 +123,19 @@ public class LCLActivity extends Activity implements SensorEventListener, Locati
       lclscreenwidth = lclformwidth;
       lclscreenheight = lclformheight;
 
-      // Check if we rotated in the draw event, OnConfigurationChanged can't return the new form width =(
+      // Check if we rotated in the draw event.
+      // LCLOnConfigurationChanged is called from here because the Android event
+      // OnConfigurationChanged can't return the new form width =(
       // see http://stackoverflow.com/questions/2524683/how-to-get-new-width-height-of-root-layout-in-onconfigurationchanged
       if (lWidth != oldlclformwidth) LCLOnConfigurationChanged(lclxdpi, lWidth); // we send xdpi because thats what the LCL uses for Screen.PixelsPerInch
 
       //Log.v("lclproject", "LCLSurface.onDraw width=" + Integer.toString(lWidth)
       //  + " height=" + Integer.toString(lHeight));
- 
-      Bitmap localbitmap = Bitmap.createBitmap(lWidth, lHeight, Bitmap.Config.ARGB_8888);
-      LCLDrawToBitmap(lWidth, lHeight, localbitmap);
-      canvas.drawBitmap(localbitmap, 0, 0, null);
+
+      if ((canvasbitmap == null) || (canvasbitmap.getWidth() != lWidth) || (canvasbitmap.getHeight() != lHeight))
+	canvasbitmap = Bitmap.createBitmap(lWidth, lHeight, Bitmap.Config.ARGB_8888);
+      LCLDrawToBitmap(lWidth, lHeight, canvasbitmap);
+      canvas.drawBitmap(canvasbitmap, 0, 0, null);
       //Log.i("lclapp", "onDraw finished");
     }
 

lcl/interfaces/customdrawn/customdrawnint.pas

@@ -91,6 +91,9 @@ type
   end;
   {$endif}
 
+  // Return true to disable the form background drawing
+  TDisableFormBackgroundDrawingProc = function (AForm: TCustomForm): Boolean of object;
+
   { TLazCDCustomFont }
 
   TLazCDCustomFont = class(TFPCustomFont)
@@ -304,6 +307,15 @@ type
     {$ifdef WinCE}
     WinCETitlePolicy: TWinCETitlePolicy;
     {$endif}
+
+    // This callback might be set to provide a routine which will select for
+    // which forms the drawing of the background should be disabled
+    // This is provided for speeding up the drawing
+    //
+    // Only use it if you are 100% sure that you are filling the entire buffer
+    // in the form paint event. Note that the form might sometimes be smaller
+    // then the buffer in Android so fill the entire Canvas area, not only the form size
+    DisableFormBackgroundDrawingProc: TDisableFormBackgroundDrawingProc;
   end;
 
 var

lcl/interfaces/customdrawn/customdrawnproc.pas

@@ -579,8 +579,16 @@ begin
 
   // Disable the drawing itself, but keep the window org and region operations
   // or else clicking and other things are broken, specially in Android
-  lDrawControl := lWindowHandle.IsControlBackgroundVisible();
-
+  //
+  // If the form is smaller then the buffer (this might happen in Android)
+  // then we need to force drawing the background to erase old contents of the buffer
+  //
+  // Consider also if the user wants to manually disable the background drawing
+  lDrawControl := True;
+  if Assigned(CDWidgetset.DisableFormBackgroundDrawingProc) then
+    lDrawControl := CDWidgetset.DisableFormBackgroundDrawingProc(AForm);
+  if lDrawControl then
+    lDrawControl := lWindowHandle.IsControlBackgroundVisible() or (AForm.Height < AImage.Height);
   if lDrawControl then
     DrawFormBackground(AImage, ACanvas);