EMF problem?

srod · Post by **srod** » Sat Oct 25, 2008 4:03 pm

Hi,

I've had this sort of thing before with Enhanced MetaFiles, but solved the previous problem. This one is proving very puzzling indeed!!!

Basically, create a small EMF containing an image and some text. No problem. 'Play' this EMF into a larger EMF and generally - no problem.

However, the following code plays the smaller memory based EMF into a larger disc based one 3 times (one under the other). The first two copies appear fine. In the third one, however, the image disappears leaving just the text!!! This one has me stumped!

Code: Select all

LoadImage(1, "header.bmp")  ;Use your own image.

hdc = CreateEnhMetaFile_(0, 0, 0, 0)
If hdc
  ;Create a small memory based EMF with a copy of the image and some text.
    hBrush = GetStockObject_(#WHITE_BRUSH)
    SetRect_(rc.RECT, 0, 0, 1000, 1000)
    oldBrush = SelectObject_(hdc, hBush)
    Rectangle_(hdc, 0, 0, 1000, 1000)
    hdcImage = CreateCompatibleDC_(hdc)
    oldImage = SelectObject_(hdcImage, ImageID(1))
      StretchBlt_(hdc, 0, 0, 1000, 400, hdcImage, 0, 0, ImageWidth(1), ImageHeight(1), #SRCCOPY)
      TextOut_(hdc, 0,500,@"HELLO!",6)
    SelectObject_(hdcImage, oldImage)
    SelectObject_(hdc, oldBrush)
    DeleteDC_(hdcImage)
    hEMF = CloseEnhMetaFile_(hdc)

  ;Render to a larger filebased emf.
    If hEMF
      hdc = CreateEnhMetaFile_(0, @"test.emf", 0, 0)
      hBrush = GetStockObject_(#GRAY_BRUSH)
      SetRect_(rc.RECT, 0, 0, 1000, 3000)
      FillRect_(hdc, rc, hBrush)
      SetRect_(rc.RECT, 0, 0, 1000, 500)
      PlayEnhMetaFile_(hdc, hEMF, @rc) 
      SetRect_(rc.RECT, 0, 500, 1000, 1000)
      PlayEnhMetaFile_(hdc, hEMF, @rc) 
      SetRect_(rc.RECT, 0, 1000, 1000, 1500)  ;Only the text appears here!!!!!! Where is the image?
      PlayEnhMetaFile_(hdc, hEMF, @rc) 
      hEMFPage = CloseEnhMetaFile_(hdc)
      DeleteEnhMetaFile_(hEMFPage) 
    EndIf
    DeleteEnhMetaFile_(hEMF) 
EndIf

To run the code, provide your own bitmap, run the program and have a look at the resulting disc file "test.emf" and you should see what I mean!!! If we play the smaller EMF into the larger and position it beyond a certain limit (vertically) then the bitmap image does not appear to get copied!

I've tried resetting view-point origins etc. but to no avail!

Any ideas what is going on here?

Thanks.

Fluid Byte · Post by **Fluid Byte** » Sat Oct 25, 2008 4:35 pm

If I understood correctly then in the third block the image is not drawn, right?

I just tested the code with another image from the PB folder.

This is what I got: http://www.codedreality.de/tl_files/temp/emftest.jpg

Should it look something like that or is it still wrong?

srod · Post by **srod** » Sat Oct 25, 2008 6:27 pm

Yes it should look exactly like that!!!

I've just used the same image as yourself from the PB folder and I still get the problem!!!

Could you please check out the emf produced on my machine and tell me if it looks the same on your machine as the image you produced?

www.purecoder.net/test.emf

Thanks.

Fluid Byte · Post by **Fluid Byte** » Sat Oct 25, 2008 6:33 pm

Nope, the image from the third block is still missing. Weird!

milan1612 · Post by **milan1612** » Sat Oct 25, 2008 6:35 pm

Yet another Vista EMF bug srod?

srod · Post by **srod** » Sat Oct 25, 2008 6:36 pm

I've tried on vista and xp on this machine with the same result.

Time to try another computer entirely...

srod · Post by **srod** » Sat Oct 25, 2008 7:29 pm

Right, same problem on my other machine (xp sp3).

@Fluid or Milan or anyone : This problem seems to surface if I play the memory emf 'far enough' down (vertically) the larger file. Perhaps we need to extend the range in order for the problem to surface on your machine.

Would you mind running the following which should place 10 copies of the emf one under the other etc. Are any of these copies missing the image?

Code: Select all

LoadImage(1, #PB_Compiler_Home+"Examples\Sources\Data\Background.bmp")

hdc = CreateEnhMetaFile_(0, 0, 0, 0) 
If hdc 
  ;Create a small memory based EMF with a copy of the image and some text. 
    hBrush = GetStockObject_(#WHITE_BRUSH) 
    SetRect_(rc.RECT, 0, 0, 1000, 1000) 
    oldBrush = SelectObject_(hdc, hBush) 
    Rectangle_(hdc, 0, 0, 1000, 1000) 
    hdcImage = CreateCompatibleDC_(hdc) 
    oldImage = SelectObject_(hdcImage, ImageID(1)) 
      StretchBlt_(hdc, 0, 0, 1000, 400, hdcImage, 0, 0, ImageWidth(1), ImageHeight(1), #SRCCOPY) 
      TextOut_(hdc, 0,500,@"HELLO!",6) 
    SelectObject_(hdcImage, oldImage) 
    SelectObject_(hdc, oldBrush) 
    DeleteDC_(hdcImage) 
    hEMF = CloseEnhMetaFile_(hdc) 

  ;Render to a larger filebased emf. 
    If hEMF 
      hdc = CreateEnhMetaFile_(0, @"test.emf", 0, 0) 
      hBrush = GetStockObject_(#GRAY_BRUSH) 
      SetRect_(rc.RECT, 0, 0, 1000, 10000) 
      FillRect_(hdc, rc, hBrush) 
      For i = 0 To 9
        SetRect_(rc.RECT, 0, i*500, 1000, (i+1)*500) 
        PlayEnhMetaFile_(hdc, hEMF, @rc) 
      Next
      hEMFPage = CloseEnhMetaFile_(hdc) 
      DeleteEnhMetaFile_(hEMFPage) 
    EndIf 
    DeleteEnhMetaFile_(hEMF) 
EndIf

Thanks.

Fluid Byte · Post by **Fluid Byte** » Sat Oct 25, 2008 7:53 pm

First 3 are shown, the rest are blank.

srod · Post by **srod** » Sat Oct 25, 2008 7:56 pm

Fluid Byte wrote:First 3 are shown, the rest are blank.

Thanks.

This means that either there is something about EMF's which I do not understand, or there is a bug here in Windows itself.

milan1612 · Post by **milan1612** » Sat Oct 25, 2008 8:13 pm

Same here - 3 are displayed correctly and the last 7 ones are missing

Okay, this rules out a machine dependant problem, either it's the code or a bug indeed...

srod · Post by **srod** » Sat Oct 25, 2008 8:32 pm

I came across it in some very complex code of mine and was surprised to find that I could replicate the problem so easily.

I am just trawling through as much info on EMF's as I can find right now to see if there is anything I am missing? If not then I will just have to find some workaround. I will be interested to enumerate all the records within the large EMF to see if I can find just eactly what is amis?

Trond · Post by **Trond** » Sat Oct 25, 2008 8:56 pm

Windows 95: PlayEnhMetaFile is subject to the limitations of the Windows 95 GDI. For example, Windows 95 supports only 16-bit signed coordinates. For records that contain 32-bit values, Windows 95 fails to play the record if the values are not in the range -32,768 to 32,767.

Maybe they forgot to fix that for Vista?

srod · Post by **srod** » Sat Oct 25, 2008 9:00 pm

We have no problem with text and other gdi elements Trond - it's just bitmaps and this only occurs when playing an EMF containing such images into another EMF. It's all very strange.

Trond · Post by **Trond** » Sat Oct 25, 2008 9:06 pm

This was regarding PlayEnhMetaFile(). You don't use that for bitmaps and text, right?

srod · Post by **srod** » Sat Oct 25, 2008 9:12 pm

Sure I do. The memory based EMF in the code above has images and text added to it which is no problem. As I say it's when playing this emf into another emf that problems arise with the images for some reason.