Spirograph (BeOS app) doesn't draw its background transparent

[jscipione]

Draws spirographs similar to a popular toy. Problem as stated by packager:

"But the transparency does not work on Haiku, so you will only see the top layer."

I've included some screenshots

[jscipione]

Screenshot on BeOS

[jscipione]

Screenshot on Haiku, notice the color #777477 which is B_TRANSPARENT_COLOR's hex value

[pulkomandy]

Peeking at the window/view structure with hey may provide some hints: how the views are laid out, which drawing modes they are using, etc.

[jscipione]

This appears to be the malfunctioning bit of code

int32 DrawView::Rewrite_image(DrawView*  data)
{
	rgb_color Transparent;
	memcpy (&Transparent, &B_TRANSPARENT_MAGIC_RGBA32, 4);

		// We'll add a drawing view to the bitmap
	int i;		// Index for the loop - we'll need it later
	BView* drawer = new BView (
		data->image->Bounds(),
		"drawer",
		B_FOLLOW_LEFT | B_FOLLOW_TOP,
		B_WILL_DRAW | B_SUBPIXEL_PRECISE);
			// If allocated successfully, add it to the bitmap
	if (drawer != NULL) {
		data->image->AddChild(drawer);
	}

			// Now, adding the image layers, one by one
			// The drawing mode must be set to B_OP_MODE, for the LowColor
			// of the drawing shall be treated as transparent.
			//
			// I must acquire the lock!
	if ( drawer->LockLooper() ) {
		drawer->SetLowColor(Transparent);
		drawer->SetViewColor(Transparent);
		drawer->SetDrawingMode(B_OP_OVER);
		for (i=0; i<MAX_LAYERS-1; i++) {
				// If current layer is not empty
			if ( (data->layers[i] != NULL) && ( (int )data->layers[i] != 0x19) ) {
					// Adding it to the bitmap, in B_OP_OVER mode
				drawer->DrawBitmap (data->layers[i]);
				drawer->Sync();
			}
		}
		drawer->UnlockLooper();
	}
	else {			// If I can't lock the BView, I alert the user.
		BAlert* cantLockLooper = new BAlert(NULL, "Cannot acquire the lock on the drawing element!", "Ok");
		cantLockLooper->Go();
	}

	// Now we may successfully delete the "drawer" BView
	data->image->RemoveChild (drawer);
	delete drawer;
	drawer = NULL;

	exit_thread(0);
	return 0;
}