BitBlt

[RichardVasey]

Ok I am writing a game in VB and have created my board from Bitmap squares, by using the BitBlt function. However I now need to put my character on the board, but make its background transparent so it is not surrounded by a square box.

The character is in .gif format with a transparent background but when I place it on the board using BitBlt there is still a boarder on it.

Can it not be done using BitBlt? Is their another way?

[Microbasic]

Make a MASK PICTURE - that is - a picture with black pixels on pixels you want to be painted and white on pixels that you don't. Make sure that your BGColor is black (if you want to draw black pixels, make those pixels black on the mask picture).

Now, start by BitBlting the mask with the opcode SRCAND. Now, Bitblt the character on with the opcode SRCPAINT.

[Microbasic]

Alternatively, you can use TransparentBlt (see MSDN for details)

[Yhoko]

TransparentBlt causes memory lacks, don't use it.

[Zaei]

I've heard that too. Doing a standard Blt with masks is probably the best bet.

Z.

[Microbasic]

Originally posted by Yhoko
TransparentBlt causes memory lacks, don't use it.

Good point - forgot about that.

With VB's paintpicture, my game costed approx. 15-25% of my GDI memory overall and with TransparentBlt, 91% and rising!