Question

I am writing a View that should show a drawable that seems to “never end”.
It should be twice or third the displaysize and move slow through the display.

Therefore I studied some samplecode by Google and found the important Lines

public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    canvasWidth = width;
    canvasHeight = height;
    float sf = backgroundImage.getWidth() / canvasWidth;
    backgroundImage = Bitmap.createScaledBitmap(backgroundImage,
        (int) (canvasWidth * sf), canvasHeight, true);
    }

To rescale the image and than

        // decrement the far background
        backgroundXPos = backgroundXPos - DELTAMOVE;
        // calculate the wrap factor for matching image draw
        int newFarX = backgroundImage.getWidth() - (-backgroundXPos);
        // if we have scrolled all the way, reset to start
        if (newFarX <= 0) {
            backgroundXPos = 0;
            // only need one draw
            canvas.drawBitmap(backgroundImage, backgroundXPos, 0, null);

        } else {
            // need to draw original and wrap
            canvas.drawBitmap(backgroundImage, backgroundXPos, 0, null);
            canvas.drawBitmap(backgroundImage, newFarX, 0, null);
        }

To draw the moving image. The images is already moving, it’s fine.

But, and this is the point of my question, the image looks very ugly. Its original is 960*190 pixels by 240ppi. It should be drawn inside a view with 80dip of height and “fill_parent” width.

It should look same (and good) on all devices. I have tried a lot but I don’t know how to make the picture look nice.

Thanks for your help.
Best regards,
Till

Answer 1

Since you’re saying that it’s a never ending drawable, probably you’re writing a game of some sort. If your image is a pixel-art type, then you don’t want any scaling; pixel-art-type images cannot be scaled and keep its crisp look (you can try using nearest neighbor interpolation and scaling to an integer multiple of the original, which sometimes might work, but sometimes you will still need manual tweaks). This is the rare case where you actually would need to have different image resource for different screen resolutions.

Otherwise you might want to use a vector image, but if — as you said — your original is a high resolution image, then vector image probably won’t help much here.

btw, you probably want to show some screenshot. “Looks ugly” is just as helpful as saying my code does not work.