Replace already drawn bitmap on SK Canvas at particular point

Asked Apr 28 '20 at 13:19

Active Jul 01 '20 at 04:58

Viewed 173 times

I wanted to update the existing bitmap drawn >@particular coords> on SK Canvas, while calling InvalidateSurface am able to draw but the previous bitmap is not clearing. New Image is beneath the older one! Canvas.Clear(0) didn't clear all previous bitmaps.

Needed help in getting over this issue.

void OnCanvasViewPaintSurface(object sender, SKPaintSurfaceEventArgs args)
{
    canvas.Clear(0) // Dont seems be clearing old Bitmaps
    if (condition)
    {
        using (Stream streami = assembly.GetManifestResourceStream(resourceID))
        {

            resourceBitmap = SKBitmap.Decode(streami);
        }

        canvas.DrawBitmap(resourceBitmap, listPoint);
    }
    else
    {
        using (Stream streami = assembly.GetManifestResourceStream(secondID))
        {

            secondBitmap = SKBitmap.Decode(streami);
        }
        canvas.DrawBitmap(secondBitmap, listPoint); // Drawn beneath the older
    }
}

Now the if condition changed to true outside the code blocks with new value again calling canvasView.InvalidateSurface(); Doest not clear previous

edited Jul 01 '20 at 04:58

Matthew

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asked Apr 28 '20 at 13:19

Tech Cruize

Could you provide some code example? – Jan Nepraš Apr 28 '20 at 13:34
you need to show us the code where you are adding the bitmaps to the canvas and drawing them – Jason Apr 28 '20 at 13:43
Updated my question, my problem is canvas.Clear() did not clear all bit maps. Let me know if you need more info. – Tech Cruize Apr 28 '20 at 13:52
2

this logic works fine for me – Jason Apr 28 '20 at 14:48
Is there a way to remove or canvas.Undraw like methods to make sure I manually remove previous? – Tech Cruize Apr 28 '20 at 15:00
2

use the Clear() method. If this isn't working then I suspect something else is going on in your code – Jason Apr 28 '20 at 15:04
Sure thing! Take care – Tech Cruize Apr 28 '20 at 15:43
2

@TechCruize So you have one solution about your problem?If yes, please give one reply about your solution. – Cherry Bu - MSFT Apr 29 '20 at 08:00

Replace already drawn bitmap on SK Canvas at particular point

0 Answers0