Android : How to convert view to Bitmap, without capturing background screen

Question

For my application, i have used pinch zoom feature by adapting from the tutorial and creating a custom view http://www.zdnet.com/blog/burnette/how-to-use-multi-touch-in-android-2-part-6-implementing-the-pinch-zoom-gesture/1847

Right now i'm working on capturing the zoomed image as bitmap.

Partially I was able to get the bitmap by making use of

setDrawingCacheEnabled(true);
Bitmap bm = Bitmap.createBitmap(finalView.getDrawingCache());
setDrawingCacheEnabled(false);

Using this approach, I'm getting both the zoomed image and the screen background.

Is there any way to capture only the zoomed image as a bitmap?

score 0 · Answer 1 · answered Sep 03 '17 at 11:00

This original answer here, just replace the setting background part. Hopefully it helps

public static Bitmap getBitmapFromView(View view) {
    if (view == null) return null;
    //Define a bitmap with the same size as the view
    Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
    //Bind a canvas to it
    Canvas canvas = new Canvas(returnedBitmap);
    // draw white background on the canvas
    canvas.drawColor(Color.WHITE);
    // draw the view on the canvas
    view.draw(canvas);
    //return the bitmap
    return returnedBitmap;
}

score 0 · Answer 2 · answered Dec 08 '11 at 17:30

0

Try

setDrawingCacheEnabled(false)
finalView.setDrawingCacheEnabled(true);
Bitmap bm = Bitmap.createBitmap(finalView.getDrawingCache());
finalView.setDrawingCacheEnabled(false);

answered Dec 08 '11 at 17:30

weakwire

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try to destroyDrawingCache after the first line please – weakwire Dec 08 '11 at 17:43
I have tried setDrawingCacheEnabled(false); destroyDrawingCache(); – Jitendar M Dec 08 '11 at 17:48
but same result, getting background in the bitmap.. . – Jitendar M Dec 08 '11 at 17:48

score 0 · Accepted Answer · edited May 23 '17 at 10:08

After having searched a lot, I found a 'Temporary' solution in the same Community & also thanks for the code from 'weakwire' provided in the same post.

Getting coordinates and width/height from a matrix

Idea is simple, all i have do is remove the background screen from the scaled image by cropping. Code is bit lengthy, but worked for me.

First get the Original Bitmap size

float imgWidth = imgBitmap.getWidth()   
float imgHeight = imgBitmap.getHeight()

Obtain the matrix ( pinch zoom feature used in my application uses matrix 'trick') values, used to scale the image and get the scaledWidth & scaledHeight of the original image.

float[] values = new float[9];
matrix.getValues(values);
float globalX = values[2];
float globalY = values[5];
float scaledWidth = values[0]*imgWidth;
float scaledHeight = values[4]*imgHeight;   

// If zoomed Image gets out of screen, I'm trying to crop the image available in the screen by considering image from (0,0)

if(globalX<0)
globalX = 0;

if(globalY<0)
globalY = 0;

Finally capture the View and crop the background In my case ("finalView" is the custom View name, where pinch zooming happens)

setDrawingCacheEnabled(false);
destroyDrawingCache();
finalView.setDrawingCacheEnabled(true);
Bitmap bm = Bitmap.createBitmap(finalView.getDrawingCache());
finalView.setDrawingCacheEnabled(false);    

//Final Image Width &  Height

int finalWidth = Math.min((int)width,(int)finalView.getWidth());
int finalHeight = Math.min((int)height,(int)finalView.getHeight());

// crop to get the scaled image

 Bitmap finalBitmap = Bitmap.createBitmap(bm, (int)globalX, (int)globalY, finalWidth ,finalHeight);

Though this is a temporary solution, it works for me. If there is any alternate solution, please post it.

Android : How to convert view to Bitmap, without capturing background screen

3 Answers3