iOS Question Sniper Effect

[Descartex]

Hi.
I need to implement a "sniper effect" on my image cropping code. I mean, it needs to behave similar to WhatsApp image selection...
I have a circle that limits the desired part of the pic, but i need to shadow the rest of the screen that is not inside this circle...
Thanks in advance.

 

[Erel]

Don't draw directly on the image. Draw on a layer that sits above it. Fill the drawing layer with a semitransparent color and erase a circle in the target point.

 

[Descartex]

Sorry, but i dont understand what should i do...
I have the image loaded on a WebView to be able to zoom in and zoom out.
Above it, i have a panel with rounded corners that makes the selection to a canvas...
How can i delete the shadowed that is not within the selection panel?
Sorry, it can be obvious, but i dont see it...

 

[Erel]

How do you find the correct region behind the panel? How do you calculate the image offset and zoom inside the WebView?

 

[Descartex]

This is my crop button code:

imT.Initialize()
    Dim iv As ImageView
    iv.Initialize("")
    iv.SetLayoutAnimated(0, 1, 0,0,WebView1.Width,WebView1.Height)
    Dim cvs As Canvas
    cvs.Initialize(iv)
    cvs.DrawView(WebView1, cvs.TargetRect)
    Log(WebView1.Width)
    cvs.Refresh
    Dim bm As Bitmap
    bm=cvs.CreateBitmap
    ImageView1.Bitmap=bm
    Dim sx,sy As Float
    sx=ImageView1.Bitmap.Width/ImageView1.Width
    sy=ImageView1.Bitmap.Height/ImageView1.Height
    ImageView1.Bitmap=imT.CropImageRect(ImageView1.Bitmap,pnlCrop.Left*sx,pnlCrop.Top*sy,pnlCrop.Width*sx,pnlCrop.Height*sy)

Where imT is an ImageTransformation object.
Thanks.

 

[Erel]

Can you upload a project with your current implementation?

 

[Descartex]

https://dl.dropboxusercontent.com/u/7930942/CropImages.zip
File Size is 800 Kb.
Thanks.

 

[Erel]

Check the attached example. The panel is not moved.
Instead a hole is drawn:

Sub pnlCrop_Touch(Action As Int, X As Float, Y As Float)
   cvsCrop.DrawColor(0)
   cvsCrop.DrawColor(0xaa000000)
   cvsCrop.DrawCircle(X, Y, 100dip, 0, True, 0)
   cvsCrop.Refresh
End Sub

You will need to store the coordinates and later use them for the crop method (I haven't implemented it).

 

[Descartex]

Simply perfect.
Thank you so much.