[Resolved] Image Flipping with BitBlt?

[The Hobo]

How can I use BitBlt to flip an image horizontally? I'm figuring I just have to mess with the x, y, width, height, but I can't seem to figure it out. I tried searching, but just saw some examples using PaintPicture. I tried to replicate it using BitBlt but just got a blank image.

Any ideas?

[dglienna]

Easy with PainPicture:

Flipping graphics vertically and/or horizontally

You can flip graphics very simply, by using the PaintPicture method of picture boxes and forms. You use a negative height and/or width to make the picture flip.

Normal, straight copy:

Picture2.PaintPicture Picture1.Picture, 0, 0, _
Picture1.Width, Picture1.Height, 0, 0, _
Picture1.Width, Picture1.Height, vbSrcCopy

Horizontal flip:

Picture2.PaintPicture Picture1.Picture, 0, 0, _
Picture1.Width, Picture1.Height, Picture1.Width, _
0, -Picture1.Width, Picture1.Height, vbSrcCopy

Vertical flip:

Picture2.PaintPicture Picture1.Picture, 0, 0, _
Picture1.Width, Picture1.Height, 0, Picture1.Height, _
Picture1.Width, -Picture1.Height, vbSrcCopy

Horizontal and Vertical flip:

Picture2.PaintPicture Picture1.Picture, 0, 0, _
Picture1.Width, Picture1.Height, Picture1.Width, _
Picture1.Height, -Picture1.Width, -Picture1.Height, vbSrcCopy

http://www.mentalis.org/tips/tip103.shtml

[chemicalNova]

I don't think the BitBlt function works the same way as the PaintPicture function, hence why you end up with a blank image. You can either use the easy PaintPicture method, or possibly use Set/GetBitmapBits to reverse it (which would be a bit faster, but alot harder).

chem

[The Hobo]

I tried searching, but just saw some examples using PaintPicture. I tried to replicate it using BitBlt but just got a blank image.

I'm looking for a way to do it with BitBlt?

[The Hobo]

I don't think the BitBlt function works the same way as the PaintPicture function, hence why you end up with a blank image. You can either use the easy PaintPicture method, or possibly use Set/GetBitmapBits to reverse it (which would be a bit faster, but alot harder).

chem

I found an example somewhere here on VBForums doing it with StretchBlt, and I thought StretchBlt was just an extension of BitBlt, so I figured there'd be a way to do it with BitBlt.

[The Hobo]

Here's the code with StretchBlt:

StretchBlt picScreen.hdc, picSource.ScaleWidth, 0, -picSource.ScaleWidth, picSource.ScaleHeight, _
    picSource.hdc, 0, 0, picSource.ScaleWidth, picSource.ScaleHeight, vbSrcCopy

I have no problem using StretchBlt, but I'm still wondering if it's possible with BitBlt?

[penagate]

BitBlt does a direct bit copy, so there is no way to flip it, unlike with StretchBlt.