Using method -canvas.drawBitmap(bitmap, src, dst, paint)

Question

Everytime I use this code nothing is drawn. I need to draw a bitmap inside of a specified rectangle.

canvas.drawBitmap(MyBitmap, null, rectangle, null)
         


        

Answer 1

The main item to remember when defining the Rect is:

• left < right and top < bottom

The rect is in screen coordinates (positive Y downward) ...

I find it helpful to think of the Rect arguments

(left, top, right, bottom)

as

(X, Y, X + Width, Y + Height)

where X,Y is the top left corner of the sprite image.

NOTE: If want to center the image on a particular location, remember to offset those values by half the sprite width & height. For example:

int halfWidth = Width/2;
int halfHeight = Height/2
Rect dstRectForRender = new Rect( X - halfWidth, Y - halfHeight, X + halfWidth, Y + halfHeight );
canvas.drawBitmap ( someBitmap, null, dstRectForRender, null );

This uses the whole original image (since src rect is null) and scales it to fit the size and position from dstRectForRender ... and using the default Paint.