screenshot bitmap

[git-bone]

Hi there,

is it possible in mapsforge vtm to create a bitmap of a mapview? i've tried with drawing on canvas and even pixelcopy. Maybe i'm doing something wrong here, but all bitmaps are blank. Use case is showing miniature bitmaps of a rendered map at a certain zoom level. There seems to be nothing out of the box in mapsforge vtm for this purpose?

[devemux86]

Android or desktop?

This is OpenGL, better search online how to take OpenGL screenshots from Android GLSurfaceView or desktop libGDX.

[demiantres]

You can use these functions:

glPixelStorei(GL_PACK_ALIGNMENT, 1);

glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, buffer_to_write_to);

[git-bone]

yep, thanks! to both of you. I found a way that seems to work :)

edit: hm, this only seems to work when the mapView is actually visible on the screen (android). This is the code I use in the main activity where the map currently renders in a layout. However I would like this to all happen in memory. Any pointers on how to do that? without rendering in a view, it gives me this error: IllegalArgumentException: Surface isn't valid, source.isValid() == false

private fun getBitMapFromSurfaceView(view: MapView, callback: (Bitmap?) -> Unit) {
val bitmap: Bitmap = Bitmap.createBitmap(
view.width,
view.height,
Bitmap.Config.ARGB_8888
)
try {
// Create a handler thread to offload the processing of the image.
val handlerThread = HandlerThread("PixelCopier")
handlerThread.start()
PixelCopy.request(
view, bitmap,
{ copyResult ->
if (copyResult == PixelCopy.SUCCESS) {
callback(bitmap)
}
handlerThread.quitSafely()
},
Handler(handlerThread.looper)
)
} catch (e: IllegalArgumentException) {
callback(null)
e.printStackTrace()
}
}

[demiantres]

You can render the map into an OpenGL frame buffer object.