CODEWITHSUNDEEP
androidbitmap
sunil
sunil

Reputation: 9681

Converting a view to Bitmap without displaying it in Android?

I will try to explain what exactly I need to do.

I have 3 separate screens say A,B,C. There is another screen called say HomeScreen where all the 3 screens bitmap should be displayed in Gallery view and the user can select in which view does he wants to go.

I have been able to get the Bitmaps of all the 3 screens and display it in Gallery view by placing all the code in HomeScreen Activity only. Now, this has complicated the code a lot and I will like to simplify it.

So, can I call another Activity from HomeScreen and do not display it and just get the Bitmap of that screen. For example, say I just call HomeScreen and it calls Activity A,B,C and none of the Activities from A,B,C are displayed. It just gives the Bitmap of that screen by getDrawingCache(). And then we can display those bitmaps in Gallery view in HomeScreen.

I hope I have explained the problem very clearly.

Please let me know if this is actually possible.

Upvotes: 161

Views: 140499

Answers (14)

Sagan
Sagan

Reputation: 112

There are multiple decent answers here but I think this is the way it should be done using the proper measure/layout/draw logic.

@Nullable
public static Bitmap captureBitmap(@NonNull View view){
    ViewGroup.MarginLayoutParams mlp = new ViewGroup.MarginLayoutParams(0, 0);
    if(view.getLayoutParams() instanceof ViewGroup.MarginLayoutParams){
        mlp = (ViewGroup.MarginLayoutParams) view.getLayoutParams();
    }
    int parentWms = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    int parentHms = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    int wms = ViewGroup.getChildMeasureSpec(parentWms,
            view.getPaddingLeft() + view.getPaddingRight() + mlp.leftMargin + mlp.rightMargin,
            view.getLayoutParams().width);
    int hms = ViewGroup.getChildMeasureSpec(parentHms,
            view.getPaddingTop() + view.getPaddingBottom() + mlp.topMargin + mlp.bottomMargin,
            view.getLayoutParams().height);
    view.measure(wms, hms);
    view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
    if(view.getMeasuredWidth()<=0 || view.getMeasuredHeight()<=0){
        return null;
    }
    Bitmap bitmap = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    view.draw(canvas);
    return bitmap;
}

If you are using a view that measures any dimension as MATCH_PARENT you need to specify parent dimensions, well at least in the direction of measurement. If your view measures width as MATCH_PARENT then use

int parentWms = View.MeasureSpec.makeMeasureSpec(parentWidth, View.MeasureSpec.AT_MOST);

Similarly for height if your view is measured as MATCH_PARENT.

int parentHms = View.MeasureSpec.makeMeasureSpec(parentHeight, View.MeasureSpec.AT_MOST);

Upvotes: 0

Ebrahim Byagowi
Ebrahim Byagowi

Reputation: 11228

I had a similar need and developed something based on codes provided, specially the one by @Azhagthott and the brand new androidx.core.view.drawToBitmap, hopefully this will be hopeful here also,

import androidx.core.view.drawToBitmap

val view = MyCustomView(context)
view.measure(
    View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.AT_MOST),
    View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.AT_MOST)
)
view.layout(0, 0, width, height)
val bitmap = view.drawToBitmap()

Upvotes: 4

Urvish Shiroya
Urvish Shiroya

Reputation: 674

I had the same problem in my project and found a solution, which I will describe here.

public Bitmap catchBitmapFromView(View capture_view){
        if (capture_view == null) {
            return null;
        }

        capture_view.setDrawingCacheEnabled(true);

        Bitmap bitmap = Bitmap.createBitmap(capture_view.getWidth(), capture_view.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        Drawable bgDrawable = capture_view.getBackground();
        if (bgDrawable != null) {
            bgDrawable.draw(canvas);
        } else {
            canvas.drawColor(Color.WHITE);
        }
        capture_view.draw(canvas);

        capture_view.setDrawingCacheEnabled(false);
        return bitmap;
}

Upvotes: 0

Kuldeep Rathod
Kuldeep Rathod

Reputation: 31

private fun getBitmapFromView(view: View): Bitmap
{
    val returnedBitmap = Bitmap.createBitmap(view.width,
        view.height
    ,Bitmap.Config.ARGB_8888)

    val canvas = Canvas(returnedBitmap)

    //background image
    val bgDrawable = view.background

    //background image is selected
    if (bgDrawable != null){
        bgDrawable.draw(canvas)
    }
    else{
        canvas.drawColor(Color.WHITE)
    }
    
    view.draw(canvas)
    
    return returnedBitmap

}

Upvotes: 0

Azhagthott
Azhagthott

Reputation: 502

I used this just a few days ago:

fun generateBitmapFromView(view: View): Bitmap {
    val specWidth = View.MeasureSpec.makeMeasureSpec(1324, View.MeasureSpec.AT_MOST)
    val specHeight = View.MeasureSpec.makeMeasureSpec(521, View.MeasureSpec.AT_MOST)
    view.measure(specWidth, specHeight)
    val width = view.measuredWidth
    val height = view.measuredHeight
    val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
    val canvas = Canvas(bitmap)
    view.layout(view.left, view.top, view.right, view.bottom)
    view.draw(canvas)
    return bitmap
}

This code is based in this gist

Upvotes: 1

Ashish Dwivedi
Ashish Dwivedi

Reputation: 8186

Try this, 

/**
 * Draw the view into a bitmap.
 */
public static Bitmap getViewBitmap(View v) {
    v.clearFocus();
    v.setPressed(false);

    boolean willNotCache = v.willNotCacheDrawing();
    v.setWillNotCacheDrawing(false);

    // Reset the drawing cache background color to fully transparent
    // for the duration of this operation
    int color = v.getDrawingCacheBackgroundColor();
    v.setDrawingCacheBackgroundColor(0);

    if (color != 0) {
        v.destroyDrawingCache();
    }
    v.buildDrawingCache();
    Bitmap cacheBitmap = v.getDrawingCache();
    if (cacheBitmap == null) {
        Log.e(TAG, "failed getViewBitmap(" + v + ")", new RuntimeException());
        return null;
    }

    Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);

    // Restore the view
    v.destroyDrawingCache();
    v.setWillNotCacheDrawing(willNotCache);
    v.setDrawingCacheBackgroundColor(color);

    return bitmap;
}

Upvotes: 24

a.ch.
a.ch.

Reputation: 8390

There is a great Kotlin extension function in Android KTX: View.drawToBitmap(Bitmap.Config)

Upvotes: 23

Shyam Kumar
Shyam Kumar

Reputation: 919

Layout or view to bitmap:

 private Bitmap createBitmapFromLayout(View tv) {      
    int spec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    tv.measure(spec, spec);
    tv.layout(0, 0, tv.getMeasuredWidth(), tv.getMeasuredHeight());
    Bitmap b = Bitmap.createBitmap(tv.getMeasuredWidth(), tv.getMeasuredWidth(),
            Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);
    c.translate((-tv.getScrollX()), (-tv.getScrollY()));
    tv.draw(c);
    return b;
}

Calling Method: 

Bitmap src = createBitmapFromLayout(View.inflate(this, R.layout.sample, null)/* or pass your view object*/);

Upvotes: 5

android developer
android developer

Reputation: 116402

I think this is a bit better :

/**
 * draws the view's content to a bitmap. code initially based on :
 * http://nadavfima.com/android-snippet-inflate-a-layout-draw-to-a-bitmap/
 */
@Nullable
public static Bitmap drawToBitmap(final View viewToDrawFrom, int width, int height) {
    boolean wasDrawingCacheEnabled = viewToDrawFrom.isDrawingCacheEnabled();
    if (!wasDrawingCacheEnabled)
        viewToDrawFrom.setDrawingCacheEnabled(true);
    if (width <= 0 || height <= 0) {
        if (viewToDrawFrom.getWidth() <= 0 || viewToDrawFrom.getHeight() <= 0) {
            viewToDrawFrom.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
            width = viewToDrawFrom.getMeasuredWidth();
            height = viewToDrawFrom.getMeasuredHeight();
        }
        if (width <= 0 || height <= 0) {
            final Bitmap bmp = viewToDrawFrom.getDrawingCache();
            final Bitmap result = bmp == null ? null : Bitmap.createBitmap(bmp);
            if (!wasDrawingCacheEnabled)
                viewToDrawFrom.setDrawingCacheEnabled(false);
            return result;
        }
        viewToDrawFrom.layout(0, 0, width, height);
    } else {
        viewToDrawFrom.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));
        viewToDrawFrom.layout(0, 0, viewToDrawFrom.getMeasuredWidth(), viewToDrawFrom.getMeasuredHeight());
    }
    final Bitmap drawingCache = viewToDrawFrom.getDrawingCache();
    final Bitmap bmp = ThumbnailUtils.extractThumbnail(drawingCache, width, height);
    final Bitmap result = bmp == null || bmp != drawingCache ? bmp : Bitmap.createBitmap(bmp);
    if (!wasDrawingCacheEnabled)
        viewToDrawFrom.setDrawingCacheEnabled(false);
    return result;
}

Using the above code, you don't have to specify the size of the bitmap (use 0 for width&height) if you want to use the one of the view itself.

Also, if you wish to convert special views (SurfaceView, Surface or Window, for example) to a bitmap, you should consider using PixelCopy class instead. It requires API 24 and above though. I don't know how to do it before.

Upvotes: 4

Akhilesh Kumar
Akhilesh Kumar

Reputation: 796

Hope this helps

View view="some view instance";        
view.setDrawingCacheEnabled(true);
Bitmap bitmap=view.getDrawingCache();
view.setDrawingCacheEnabled(false);

Update
getDrawingCache() method is deprecated in API level 28. So look for other alternative for API level > 28.

Upvotes: 2

Ashutosh Gupta
Ashutosh Gupta

Reputation: 29

view.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache());
view.setDrawingCacheEnabled(false);

Upvotes: -3

Simon
Simon

Reputation: 13283

there is a way to do this. you have to create a Bitmap and a Canvas and call view.draw(canvas);

here is the code:

public static Bitmap loadBitmapFromView(View v) {
    Bitmap b = Bitmap.createBitmap( v.getLayoutParams().width, v.getLayoutParams().height, Bitmap.Config.ARGB_8888);                
    Canvas c = new Canvas(b);
    v.layout(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());
    v.draw(c);
    return b;
}

if the view wasn't displayed before the size of it will be zero. Its possible to measure it like this: 

if (v.getMeasuredHeight() <= 0) {
    v.measure(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    Bitmap b = Bitmap.createBitmap(v.getMeasuredWidth(), v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
    v.draw(c);
    return b;
}

EDIT: according to this post, Passing WRAP_CONTENT as value to makeMeasureSpec() doesn't to do any good (although for some view classes it does work), and the recommended method is:

// Either this
int specWidth = MeasureSpec.makeMeasureSpec(parentWidth, MeasureSpec.AT_MOST);
// Or this
int specWidth = MeasureSpec.makeMeasureSpec(0 /* any */, MeasureSpec.UNSPECIFIED);
view.measure(specWidth, specWidth);
int questionWidth = view.getMeasuredWidth();

Upvotes: 242

levigroker
levigroker

Reputation: 2136

I know this may be a stale issue, but I was having problems getting any of these solutions to work for me. Specifically, I found that if any changes were made to the view after it was inflated that those changes would not get incorporated into the rendered bitmap.

Here's the method which ended up working for my case. With one caveat, however. prior to calling getViewBitmap(View) I inflated my view and asked it to layout with known dimensions. This was needed since my view layout would make it zero height/width until content was placed inside.

View view = LayoutInflater.from(context).inflate(layoutID, null);
//Do some stuff to the view, like add an ImageView, etc.
view.layout(0, 0, width, height);

Bitmap getViewBitmap(View view)
{
    //Get the dimensions of the view so we can re-layout the view at its current size
    //and create a bitmap of the same size 
    int width = view.getWidth();
    int height = view.getHeight();

    int measuredWidth = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
    int measuredHeight = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY);

    //Cause the view to re-layout
    view.measure(measuredWidth, measuredHeight);
    view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());

    //Create a bitmap backed Canvas to draw the view into
    Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);

    //Now that the view is laid out and we have a canvas, ask the view to draw itself into the canvas
    view.draw(c);

    return b;
}

The "magic sauce" for me was found here: https://groups.google.com/forum/#!topic/android-developers/BxIBAOeTA1Q

Cheers,

Levi

Upvotes: 31

Gil SH
Gil SH

Reputation: 3868

here is my solution:

public static Bitmap getBitmapFromView(View view) {
    Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(returnedBitmap);
    Drawable bgDrawable =view.getBackground();
    if (bgDrawable!=null) 
        bgDrawable.draw(canvas);
    else 
        canvas.drawColor(Color.WHITE);
    view.draw(canvas);
    return returnedBitmap;
}

Enjoy :)

Upvotes: 37

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