android-canvas

Basically, I have a rectangular bitmap and want to create a new Bitmap with squared dimensions which will contain the rectangular bitmap inside of it. So, for example, if the source bitmap has width:100 and height:400, I want a new bitmap with width:400 and height:400. Then, draw the source bitmap centered inside of this new bitmap (see attached image for a better understanding). My code below creates the square bitmap fine, but the source bitmap is not being drawn into it. As a result, I'm left with a bitmap that is completely black. Here is the code: Bitmap sourceBitmap = BitmapFactory

It seems like Android really doesn't like invalidate (Rect dirty) , which is used to invalidate only part of a canvas. When I invalidate part of a canvas (shown in green below) and a ToggleButton outside of the canvas needs to be redrawn at the same time, the entire region shown in red is erased! It seems as though Android is just invalidating everything within the smallest rectangle encompassing the union of the two regions that need to be redrawn, even if one of the regions is outside of the View whose canvas I'm invalidating. Is this standard behaviour, and if so, why would anyone use

I'm trying to rotate my subclass of TextView using canvas.rotate() : canvas.save(); final int w = getWidth(); final int h = getHeight(); float px = w/2f; float py = h/2f; canvas.rotate(mAngle, px, py); super.draw(canvas); canvas.restore(); TextView is rotated, however bounds of my view are clipped: I understand that this is because of my view's size - it is not changed during rotation while it should. But if I'll change width\height in onMeasure problem will remain - I'm using LayoutParams.WRAP_CONTENT , so TextView just change it's size according to values provided in setMeasuredDimensions .

I'm trying to port an emulator that i have written in java to android. Things have been going nicely, I was able to port most of my codes with minor changes however due to how emulation works, I need to render image at pixel level. As for desktop java I use int[] pixelsA = ((DataBufferInt) src.getRaster().getDataBuffer()).getData(); which allow me to get the reference to the pixel buffer and update it on the fly(minimize object creations) Currently this is what my emulator for android does for every frame @Override public void onDraw(Canvas canvas) { buffer = Bitmap.createBitmap(pixelsA, 256,

Trying to achieve freehand cropping of an image, so I'm able to draw on the image. But it goes outside bitmap region. I just wanna restrict that user can only draw inside bitmap region, check below screen shot. I am trying to implement functionality like Photoshop lasso tool . Its drawing outside view region, which generates incorrect output. Output Code@ onDraw public void onDraw(Canvas canvas) { final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); canvas.drawBitmap(bitmap, rect, rect, null); // RectF r = new RectF(); // Matrix matrix = new Matrix(); // matrix.mapRect(r);