Making Bitmaps and Graphics objects - two ways

[**Developer**]

Stumbling through I find both of the following appear to work the same.

I'm guessing there is a difference that I'm just not aware of.

Can someone enlighten me?



Thanks





'This works (4 lines)

Dim TmpBitmapGraphics As Graphics = PictureBoxPic.CreateGraphics

Dim TmpBitmap As New Drawing.Bitmap(PictureBoxPic.ClientSize.Width,
PictureBoxPic.ClientSize.Height, TmpBitmapGraphics)

TmpBitmapGraphics.Dispose() 'Did the above to preserver the PixelFormat

TmpBitmapGraphics = Graphics.FromImage(TmpBitmap)

'This also works (2 lines)

Dim TmpBitmap As New Drawing.Bitmap(PictureBoxPic.ClientSize.Width,
PictureBoxPic.ClientSize.Height)

Dim TmpBitmapGraphics As Graphics = Graphics.FromImage(TmpBitmap)

 

[Guest]

Stumbling through I find both of the following appear to work the same.

I'm guessing there is a difference that I'm just not aware of.

Can someone enlighten me?



Thanks





'This works (4 lines)

Dim TmpBitmapGraphics As Graphics = PictureBoxPic.CreateGraphics

Dim TmpBitmap As New Drawing.Bitmap(PictureBoxPic.ClientSize.Width,
PictureBoxPic.ClientSize.Height, TmpBitmapGraphics)

TmpBitmapGraphics.Dispose() 'Did the above to preserver the PixelFormat

TmpBitmapGraphics = Graphics.FromImage(TmpBitmap)

'This also works (2 lines)

Dim TmpBitmap As New Drawing.Bitmap(PictureBoxPic.ClientSize.Width,
PictureBoxPic.ClientSize.Height)

Dim TmpBitmapGraphics As Graphics = Graphics.FromImage(TmpBitmap)

'Set it to the picture boxes graphics object
1. Dim TmpBitmapGraphics As Graphics = PictureBoxPic.CreateGraphics

2. Dim TmpBitmap As New Drawing.Bitmap(PictureBoxPic.ClientSize.Width,
PictureBoxPic.ClientSize.Height, TmpBitmapGraphics)

'Kill this object (this has the same effect as if you never did line 1
3. TmpBitmapGraphics.Dispose() 'Did the above to preserver the PixelFormat

' Set the object to something totally new.
4. TmpBitmapGraphics = Graphics.FromImage(TmpBitmap)

So it seems like this way of doing it is pretty pointless, since you
create the object and then just kill it right after.

 

[**Developer**]

..

'Set it to the picture boxes graphics object
1. Dim TmpBitmapGraphics As Graphics = PictureBoxPic.CreateGraphics

2. Dim TmpBitmap As New Drawing.Bitmap(PictureBoxPic.ClientSize.Width,
PictureBoxPic.ClientSize.Height, TmpBitmapGraphics)

'Kill this object (this has the same effect as if you never did line 1

Except Line 2 used it. Not sure about the effect though. Can an image in a
picturebox have different DPI? Or does it match the screen?