//--Clear the handle to the device context

DeleteDC(CompatibleHDC);
//

DeleteObject(BitmapHandle);
//

//--Unlock the memory handle

GlobalUnlock(MemoryHandle);
//

//--Return the memory handle

return MemoryHandle;

//--The BitmapHandle was failing

if(BitmapHandle == 0 || !SelectObject(CompatibleHDC, BitmapHandle))
{
	return NULL;
}

HBITMAP BitmapHandle = CreateCompatibleBitmap(SourceHDC, GENGINE.GetWindowWidth(), GENGINE.GetWindowHeight());

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When you no longer need the bitmap, call the DeleteObject function to delete it.

Windows 95/98/Me: The created bitmap cannot exceed 16MB in size.

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Original post by UltimaX
If I find out how to update the source I will. (Does anyone know how?)

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Original post by Myopic Rhino

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Original post by UltimaX
If I find out how to update the source I will. (Does anyone know how?)

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Normally, you'd just email me, but I've already updated it.

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Original post by Aeroum
Hey, this is great. I've never seen the high resolution method described before. It really is something often overlooked! And I've been wondering how to go about the video saving, and your article covered that as well. Awesome!

Also, if you tend to copy around your screenshots a lot or move them to seperate directories, it is still possible to overwrite them, which is why in my screenshot system I put in the date instead of misc incrementing numbers.

Like this
year, month, day, hour, min, second, so it sorts it in the directory correctly as well.
screen_yyyymmdd_hrmn_sc

so today, right now would be
screen_20040313_0611_37

Anyway, that's just something I found to be very very useful in numbering screenshots. And you do not even have to check if the screenshot exists already or not, unless you take screenshots very fast (you could also add miliseconds if you needed)...It's also useful if you take screenshots of various versions of the program, so in the future you can see the date and time the screenshot was taking without relying on the 'Date Modified' data.

Great article, UltimaX!!! I'm glad someone wrote about something so simple, yet so useful!

- Aeroum

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Original post by Aeroum
Oh yeah, I looked at the code and I see the file manager determines if a file exist and increments if the name is taken. But let me give you an example...

Before I would keep my debug and my release versions in seperate directories, and as I was testing I took screen shots with both. Then I wanted to put screenshots from both into the same directory, with Windows explorer, and there were like 60 files with the same name. So all I could do to keep them both in the same directory would be to first manually rename each one, 1 by 1.

You could use a batch file renamer, but putting a timestamp on the filename itself worked a lot better. With date/time on each file name, I can move screenshots from multiple directories into other directories and they all fall smoothly into place, sorted by filename and therefore by date/time.

This probably will never come up, but if it does, putting date/time could be helpful, especially if there are 100s of screens.

It's a great article and I'm not suggesting that anything be changed. Just something anyone may want to keep in mind.

- Aeroum

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Original post by SarsDP
That was a great article, that system sure beats my current method of hitting print screen

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//--Validate the memory data

        if(MemoryData)
        {
                //--Free the memory data

                free(MemoryData);
                MemoryData = NULL;
        }

        //--Free the Watermark handle

        GlobalFreePtr(MemoryData);

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Original post by Coder
Nice job!

Some constructive criticism:
- When the demo is executed in a folder that doesn't contain the watermark image, it pops an error message saying that, and then crashes. It should fail and quit.

- Debug build crashes complaining about an invalid heap pointer. This is the code that's causing the problem:

//--Validate the memory data

        if(MemoryData)
        {
                //--Free the memory data

                free(MemoryData);
                MemoryData = NULL;
        }

        //--Free the Watermark handle

        GlobalFreePtr(MemoryData);

The complaint (assertion failure) is fired from inside free. Basically, it says that the pointer supplied (MemoryData) doesn't belong to this heap. MemoryData should be freed by GlobalFreePtr, obviously. What the code does is free() MemoryData (which is causing the error), and then it always passes a NULL pointer to GlobalFreePtr.

- Using the GDI is most probably the source of the huge slow-downs. Try locking the back-buffer and mem-copying it instead, every frame. In one of my previous demos (light-scattered sky+terrain), locking the whole back-buffer reduced the frame rate from ~330 to ~150, which isn't that bad.(frame-time changed from ~0.00303 to ~0.00667).

- Supporting D3D and GL using 2 code-paths with if-else blocks is very tedious. You'd better create an "abstract" renderer (an interface) and then implement it with D3D and GL concrete classes. Or better, drop support for one of them (It consumes loads of time, and if you don't have a very good reason to justify it, just drop one of them).

- I think it'd be better to rename source-code zip packages included with articles to something more reasonable. I mean, "source.zip" causes a lot of ambiguity, unless I explicitly rename it when saving it (something I never ever did).
Making it "screenshot-system-source.zip" would be much better.

Muhammad Haggag
Bitwise account: MHaggag -

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