Author Topic: Loading an image from a .rc file (Read 14741 times)

Disch · « **Reply #15 on:** January 30, 2011, 04:54:18 pm »

Quote from: "Laurent"

LoadFromMemory takes a pointer to a bitmap file in memory (the same thing that you would have on your hard drive).

This is what I was thinking. If that's the case, then the size of the resource will almost certainly not be equal to width*height*4

JAssange · « **Reply #16 on:** January 30, 2011, 05:02:17 pm »

LoadFromMemory wants the bytes of a normal BMP file, not a Windows DIB.

Quote

This is what I was thinking. If that's the case, then the size of the resource will almost certainly not be equal to width*height*4

Sorry, was thinking of LoadFromPixels.

Laurent · « **Reply #17 on:** January 30, 2011, 05:54:36 pm »

Quote

LoadFromMemory wants the bytes of a normal BMP file, not a Windows DIB.

I'm just wondering, isn't DIB the same thing that is inside bitmap files?

JAssange · « **Reply #18 on:** January 30, 2011, 06:00:24 pm »

Quote from: "Laurent"

Quote
LoadFromMemory wants the bytes of a normal BMP file, not a Windows DIB.

I'm just wondering, isn't DIB the same thing that is inside bitmap files?

As far as I know they use a modified header.

Disch · « **Reply #19 on:** January 30, 2011, 07:27:20 pm »

I wasn't aware there was any difference, either

Prominence256 · « **Reply #20 on:** January 30, 2011, 07:35:26 pm »

Okay, I replaced

Code: [Select]

zeroimg.LoadFromMemory((const char*) lpvoid, SizeofResource(GetModuleHandle(NULL), hresource));with

Code: [Select]

zeroimg.LoadFromPixels(128, 128, (const Uint8*) lpvoid);
Now it shows a messed up version of the picture:

Groogy · « **Reply #21 on:** January 30, 2011, 07:49:18 pm »

So the image is flipped? That's not messed up, your just a step away from having it working

Prominence256 · « **Reply #22 on:** January 30, 2011, 08:39:13 pm »

It's not that it's flipped it's that it attached part of the right side to the left edge of the image. This, is what's getting drawn to the screen:

devlin · « **Reply #23 on:** January 30, 2011, 09:06:38 pm »

Seems to me you have a 10-40 byte (depending on bitdepth) header you're not removing before sending it to LoadFromPixels. It's not the stride or it would be diagonal.

Prominence256 · « **Reply #24 on:** January 30, 2011, 10:20:09 pm »

How do I get rid of the header?

devlin · « **Reply #25 on:** January 30, 2011, 10:23:17 pm »

Well, you could try it the hackish way and do:

zeroimg.LoadFromPixels(128, 128, ((const Uint8*) lpvoid) + 10); // or rather +30/+40 depending on bitdepth.

Prominence256 · « **Reply #26 on:** January 31, 2011, 01:54:34 am »

I'm using 40 as the color depth, and that problems fixed. But now it's still upside down:

devlin · « **Reply #27 on:** January 31, 2011, 10:18:51 am »

Yes, that is normal for DIBs.

From Wikipedia:

Quote

The Pixel Array is a block of 32-bit DWORDs, that describes the image pixel by pixel. Normally pixels are stored "upside-down" with respect to normal image raster scan order, starting in the lower left corner, going from left to right, and then row by row from the bottom to the top of the image.[1]
Uncompressed Windows bitmaps also can be stored from the top to bottom, when the Image Height value is negative.

Groogy · « **Reply #28 on:** January 31, 2011, 11:48:18 am »

You could before passing the pointer to the image create a temporary array where you copy each pixel but just make sure that you flip them. Then pass the array to the image and your done

Disch · « **Reply #29 on:** January 31, 2011, 04:40:12 pm »

Wait... why did you switch to LoadFromPixels? Was LoadFromMemory not working?

Loading from pixels seems like a really bad idea here. I mean you already have a header and everything -- why not just load the image normally?