B4J Question Save combined Canvas and ImageView

ElliotHC · Mar 6, 2021

I am capturing an image with a webcam and using a canvas to highlight parts of the image, I am doing this by placing the Canvas in front of it. It works very well.

Currently, when an event occurs, I am saving the image in the ImageView. However, I only have the image and not the information drawn over it with the Canvas.

Is there a way to save both together, perhaps print the screen just in the area of those two overlaid items?

DonManfred · Mar 6, 2021

1. Copy the image from the Imageview to the Canvas.
2. Draw on Canvas
3. Save the Canvas-Snapshot

ElliotHC · Mar 6, 2021

DonManfred said:
1. Copy the image from the Imageview to the Canvas.
2. Draw on Canvas
3. Save the Canvas-Snapshot

Thanks.
Ok, so how do I put whats in the imageview to a Canvas and how do I save a Canvas as an image?

DonManfred · Mar 6, 2021

B4X:

    Dim p As Pane = xui.CreatePanel("")
    p.SetLayoutAnimated(0,0,0,722,373)
    Root.AddView(p,0,0,722,373)

    p.LoadLayout("LayoutCanvas")
    Dim bmp As B4XBitmap = xui.LoadBitmapResize(File.DirAssets, "ORCLogoF1.png",722dip,373dip,True) ' Load the file you use in Imageview
    cvs.DrawImage(bmp, 0, 0, 722dip, 373dip) ' Draw Image on Canvas
    Dim fnt As Font = xui.CreateDefaultFont(20)
    cvs.DrawText("Test bla bla bla",20dip,90dip,fnt,fx.Colors.Blue,"LEFT") ' Add Text to Canvas
    Dim snap As Image = cvs.Snapshot ' Get Canvas Snapshot
    
    Dim out As OutputStream = File.OpenOutput("D:\", "CanvasImageCombined.png", False) ' Write Snapshot to Disc.
    snap.WriteToStream(out)
    out.Close

    p.RemoveNodeFromParent

ElliotHC · Mar 6, 2021

DonManfred said:

B4X:

    Dim p As Pane = xui.CreatePanel("")
    p.SetLayoutAnimated(0,0,0,722,373)
    Root.AddView(p,0,0,722,373)

    p.LoadLayout("LayoutCanvas")
    Dim bmp As B4XBitmap = xui.LoadBitmapResize(File.DirAssets, "ORCLogoF1.png",722dip,373dip,True) ' Load the file you use in Imageview
    cvs.DrawImage(bmp, 0, 0, 722dip, 373dip) ' Draw Image on Canvas
    Dim fnt As Font = xui.CreateDefaultFont(20)
    cvs.DrawText("Test bla bla bla",20dip,90dip,fnt,fx.Colors.Blue,"LEFT") ' Add Text to Canvas
    Dim snap As Image = cvs.Snapshot ' Get Canvas Snapshot
   
    Dim out As OutputStream = File.OpenOutput("D:\", "CanvasImageCombined.png", False) ' Write Snapshot to Disc.
    snap.WriteToStream(out)
    out.Close

    p.RemoveNodeFromParent

View attachment 109182

Thanks.

I think this is too much code for my project. I've looking through 640 X 480 pixels, then box searching 40 x 40. If I get a match I'm taking an image. This might really slow it down a lot if I get 30 or so matches in a frame. It's doing 4 frames a second currently.

B4J Question Save combined Canvas and ImageView

ElliotHC

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DonManfred

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ElliotHC

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ElliotHC

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