Trying to print w/GDI+ -- Help!

[NoCforMe]

I'm stuck. I'm trying to print a page using GDI+. I modified some code that works using GDI+ to display an image in a window. When I run this, I get a completely blank page out of the printer.

Here's the code, at least the relevant parts, that I'm using. Again, the non-printing parts of this code work using a window instead of a printer. I don't want to post the complete code just now; it's complicated, and I'm hoping that someone will be able to point out that I left something out here, or some other (hopefully) simple mistake I'm making.

Also, the printing stuff works; copied from another program that successfully prints a page using GDI functions. it's GDI+ that ain't working here.

I thought that printing to a printer's DC using GDI+ would be similar to using a window's DC, but apparently that may not be the case.

BTW, in case the question comes up, the reason I'm using GDI+ instead of plain old GDI is that I need to be able to use non-BMP image files, which are the only ones you can load with GDI. (Using JPEGs here.)

Thanks in advance to anyone who can throw some light on this problem!

Code Select Expand


; Use Print dialog to select printer, get handle to DC:
INVOKE PrintDlgEx, ADDR printDlgStruct

INVOKE StartDoc, printDlgStruct.hDC, ADDR docInfo
INVOKE StartPage, printDlgStruct.hDC

; Make image filename Unicode:
INVOKE MakeUnicodeName, OFFSET ImageFileName, ADDR unicodeName

; Open JPEG image file:
INVOKE GdipLoadImageFromFile, ADDR unicodeName, OFFSET GdiHbitmap

; Get width & height of bitmap:
INVOKE GdipGetImageWidth, GdiHbitmap, ADDR imgStruct.imgW
INVOKE GdipGetImageHeight, GdiHbitmap, ADDR imgStruct.imgH

; Set image X- and Y-offsets:
MOV ImgStruct.imgX, 0
MOV ImgStruct.imgY, 0

; Get graphics "object" from DC handle:
INVOKE GdipCreateFromHDC, printDlgStruct.hDC, ADDR gdiHgraphics

; Display image at (X,Y) with dimensions (W,H):
; Many thanks to "mabdelouahab" from the MASM32 forum for this.
INVOKE GdipDrawImageRectI, gdiHgraphics, GdiHbitmap,
imgStruct.imgX, imgStruct.imgY, imgStruct.imgW, imgStruct.imgH

; DOESN'T WORK!


[jj2007]

Printing from a richedit works fine for me, but I use plain GDI, so that won't help you. A quick search says GdipSetPageUnit could be an issue, but it's difficult to see your problem without full code.

I see no error checking. What do the various GDI+ calls return? All zero?

[NoCforMe]

I see no error checking. What do the various GDI+ calls return? All zero?

Checked returns, at least from GdipLoadImageFromFile(), GdipCreateFromHDC(), and GdipDrawImageRectI(): all return 0.

I put in a call to GdipSetPageUnit():

Code Select Expand


INVOKE GdipSetPageUnit, ADDR gdiHgraphics, 2


but still no joy. (I got the value 2 from the enumeration list; it means "unitPixel".)

Hmmm; GdipSetPageUnit() returned 2, but that's probably just the previous "unit" value (I'm guessing, anyhow) ...

[jj2007]

GdipSetPageUnit() returned 2, but that's probably just the previous "unit" value (I'm guessing, anyhow) ...

Code 2 is InvalidParameter

[NoCforMe]

Yes, but is that what that function returns? There are a lot of Win32 functions that set values which return the previous value instead of a status value.

[jj2007]

It's GDI+, a different animal. All GdiPlus functions return 0 for success, and non-zero means an error.

[NoCforMe]

Aaaargh. My bad. Passed a pointer to a pointer instead of the pointer itself;

Code Select Expand


INVOKE GdipSetPageUnit, gdiHgraphics, 2

fixed that. Still doesn't print anything, though.

[jj2007]

the reason I'm using GDI+ instead of plain old GDI is that I need to be able to use non-BMP image files, which are the only ones you can load with GDI. (Using JPEGs here.)

If nothing helps, you might try GdipCreateHBITMAPFromBitmap - it gives you a GDI bitmap from a GDI+ bitmap.

[NoCforMe]

That works. Thanks! Used GDI (BitBlt() ) to print and it works. That'll get me through this project.
Still disappointed that I couldn't make it work through GDI+. Last time I got some advice from "mabdelouahab" that solved my problem. Maybe by invoking his name he'll come riding in here on his white horse and give me the magic incantation I need ...

[jj2007]

Wow, excellent, you are fast

[NoCforMe]

Just bored and nothing else to do at the moment ...