Flipping An Image

[martynd]

ok im sure this is really simple, but i have looked through the 1st 15 pages of posts and cant find anyhitng

i have loaded an image into a picture box, its an inverted dib, so as its loaded as a bmp its upside down, so rather than playing with all the dib commands to load it properly i want to simply flip the image that has been loaded, is that possible?

[cyborg]

dunno what a dib is, but to flip the code, do:

Dim X As Long
Dim Y As Long
 
TempPic.Picture = Pic.Picture
 
For X = 0 To Pic.ScaleWidth
    For Y = 0 To Pic.ScaleHeight
        SetPixel Pic.hDC, X, Y, GetPixel(TempPic.hDC, Pic.ScaleWidth - X, Pic.ScaleHeight - Y)
    Next Y
Next X
 
Pic.Refresh

[Sastraxi]

The reason is that the pixel bits are actually flipped in memory, however it displays correctly when SetDIBits is used (I think). If it still isn't, you should first try the loading options, and if all else fails (I'm assuming a 2D array with datatype of BYTE):

dim x as long
dim y as long
dim tmpbyte as byte
for x = 0 to width * 3 - 1
    for y = 0 to height - 1
        tmpbyte = dib(x, y)
        dib(x, y) = dib(x, height - y) 
        dib(x, height - y) = tmpbyte
    next y
next x

[CornedBee]

cyborg: DIB stands for Device Independent Bitmap = (more or less) a bmp file.

[martynd]

how long will these take 2 flip?? its a 6 meg picture (2732x2732 pixels) i know its pretty instant in picture progs lol

would it be quicker 2 load it useing dib code?

[CornedBee]

Picture progs only flip it once (when loading it) and then simply blit the corrected version.
It's pretty fast to flip, but not so fast that you should do it everytime you draw the img.

[martynd]

when i said in progs i was refering 2 when the user clicks the flip button

i only need it flipped once (on load) so using a dib code to load would prob b faster, coz by the looks of those codes they do it line by line, its a 2732x2732 pixel image so it will take a wile i think, ill try them tonight when i get back fromwork to see ho fast or slow they are

thx for the help

[CornedBee]

You can either do it line by line or pixel by pixel. But line by line in effect comes down to pixel by pixel too.

[martynd]

i dont mind what the method is, just as long as its fast lol

[joey o.]

I use stretchblit to do flips passing in passing in a memorydc and manipulating the dest with. Make it dynamic and you can spin stuff pretty easily.

ex: stretchblit memdc(0)x,y,width-x,height,memdc(1) _ x2,y2,width2,height2,vbsrccopy

[martynd]

cheers for all your help guys, i got it working now