cropping using vb.net 2008 graphics (System.Drawing.Drawing2D)

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I have a picturebox (origBox) within a panel with auto scroll set on.
A number of lines are drawn on the origBox. Later on a graphics path is drawn on the origBox. Now I am trying to crop and magnify a part of the origBox picturebox contents (bitmap) to another picturebox (cropBox). The cropping and magnification work, but there is a problem:
I use a rectangle to select a part of the origBox. The rectangle covers image of the lines drawn directly on the origBox and part of the graphics path drawn on the origBox. However, on the cropBox, only the selected lines are displayed; the part of graphics path that was selected is missing.

Could anyone, please, explain why this happens? Is graphics path a transparent layer that is not picked by copying a part of a picturebox (eg. origBox) bitmap?

Thanks.

Posted 9-Jan-13 11:09am

captab1

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Sergey Alexandrovich Kryukov 9-Jan-13 17:19pm

Wrong way, go back! I explained it all in my answer, please see.
—SA

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Sergey Alexandrovich Kryukov · Answer 1 · 2013-01-09T11:18:00

First of all, you try to abuse PictureBox, as too many do. This control is totally useless, unless you want to do something very simple, in a very simplified way. In all other cases, it presents just hassled giving nothing in return. I'll tell you what to do instead.

Please see my past answers:
How do I clear a panel from old drawing[^],
draw a rectangle in C#[^],
Append a picture within picturebox[^].

See also:
Drawing Lines between mdi child forms[^],
capture the drawing on a panel[^],
What kind of playful method is Paint? (DataGridViewImageCell.Paint(...))[^],
How to speed up my vb.net application?[^].

And magnification is done by System.Drawing.Graphics.Transform: http://msdn.microsoft.com/en-us/library/system.drawing.graphics.transform.aspx[^].

As to cropping, it's not needed at all (if you are not using PictureBox which will only screw up it :-)). For rendering (see above), use some control of required size, all rendering will be cropped by its bounds. As simple as that.

—SA