BitmapFromFile

[korte]

Using bitmapfromfile lib(masm32).
Displayiong jpeg file.

how to determinate picture original width and height?

[MichaelW]

Starting with the HBITMAP returned by BitMapFromFile, I think you can get the dimensions by calling the GDI GetObject function, but I'm not sure how the bitmap dimensions relate to the "original" dimensions.

[zooba]

Alternatively, GetDIBits will fill in a BITMAPINFO structure (the data pointer is optional). Whether or not you get better results than with GetObject I don't know, but I've had trouble in the past with GetObject. Hopefully GetDIBits will give the right numbers, since you are supposed to be able to use them to allocate memory for the bitmap.

Cheers,

Zooba :U

[sinsi]

You could also read the original jpeg's header, since you know the filename...

[korte]

Starting with the HBITMAP returned by BitMapFromFile, I think you can get the dimensions by calling the GDI GetObject function, but I'm not sure how the bitmap dimensions relate to the "original" dimensions.

NOT work.

Code Select Expand


   invoke   BitmapFromFile,eax
   mov   hBitmap,eax
   invoke   GetObject,hBitmap,sizeof(BITMAP),addr xbitmap  <- returned 0
   invoke   GetLastError <- returned 0


hBitmap correct object
displaying ok.

[korte]

also not work

Code Select Expand



   invoke    GetDIBits,hMemDC,hBitmap,0,128,NULL,addr xbitmapinfo,DIB_RGB_COLORS
   invoke    GetLastError



but displaying correct

Code Select Expand


   invoke   BitBlt,hdc,0,0,128,128,hMemDC,0,0,SRCCOPY


[MichaelW]

Try calling GetObject with lpvObject set to NULL, then compare the return value, which should be the required size of the buffer, to the size of the buffer you are passing.

[korte]

Size OK

[zooba]

Works for me. Probably you forgot to set the biSize value:

Code Select Expand

mov xbitmapinfo.bmiHeader.biSize, SIZEOF BITMAPINFOHEADER

I also used GetDC(0) (ie. the desktop window) for my DC since I didn't create any windows.

GetObject also worked for me, though I have had it fail at other times.

Both gave me the correct pixel dimensions of the JPEG image I loaded.

Cheers,

Zooba :U

[korte]

Code Select Expand

mov xbitmapinfo.bmiHeader.biSize, SIZEOF BITMAPINFOHEADER


yes.
work
thx