Crop wallpapers to screen size

[ricks79]

Hi,
First of all, very cool app. It's exactly what I was looking for.

I have a feature request in mind. If a wallpaper does not match the screen dimensions it becomes scrolled to the side (especially if its landscape) for parallax. If I set the wallpaper from the android wallpaper picker I have the option to center it manually.
I see there is a crop wallpaper feature for smaller dimensions in the app already, which is great.
But the reverse would be really cool for achieving this centering.

[smashedr]

So just to confirm, you want to be able to crop the image, but take a center cut from the image?

This is something I have wanted to improve myself as I notice it in some of the wallpapers.

Currently this is the crop function:

app/src/main/java/org/cssnr/remotewallpaper/ui/home/HomeFragment.kt#L276

fun scaleAndCropCenter(src: Bitmap, targetWidth: Int, targetHeight: Int): Bitmap {
    // targetWidth: WallpaperManager.desiredMinimumWidth
    // targetHeight: WallpaperManager.desiredMinimumHeight
    Log.d("Cropper", "target W=$targetWidth H=$targetHeight")

    val srcWidth = src.width
    val srcHeight = src.height
    Log.d("Cropper", "src W=$srcWidth H=$srcHeight")

    val scale = maxOf(
        targetWidth.toFloat() / srcWidth,
        targetHeight.toFloat() / srcHeight
    )
    Log.d("Cropper", "scale: $scale")

    val scaledWidth = (srcWidth * scale).toInt()
    val scaledHeight = (srcHeight * scale).toInt()
    Log.d("Cropper", "scaled W=$scaledWidth  H=$scaledHeight")

    val scaledBitmap = src.scale(scaledWidth, scaledHeight)

    val x = (scaledWidth - targetWidth) / 2
    val y = (scaledHeight - targetHeight) / 2
    Log.d("Cropper", "x=$x  y=$y")

    return Bitmap.createBitmap(scaledBitmap, x, y, targetWidth, targetHeight)
}

The result on a 1280x720 device:

target W=2560 H=1280
src W=1920 H=1080
scale: 1.3333334
scaled W=2560  H=1440
x=0  y=80

I will play around with this when I get some time. I am open to any suggestions tho.

[ricks79]

yes exactly,

I have the following theory in mind:

Lets assume The device dimensions are Dx and Dy and the image dimensions are Ix and Iy.

1. If Ix < Dx or Iy < Dy, we simply scale up to ensure both are greater than or equal to (unless somone wants black bars, frankly nobody does other than movie directors :))

2. Now since above is done, Ix >= Dx && Iy >= Dy evaluates to true, for centering we call the method Bitmap.createBitmap(scaledBitmap, (Ix - Dx)/2, (Iy - Dy)/2, Dx, Dy)