MAMEWorld Forums - EmuChat

Looking at the source for rendlay.c, you definitely have the order correct. The representation is an 8-bit bitmap where a one indicates an "on" segment. The first seven bits represent the segments you've identified, while the eighth bit is used for a decimal point segment.

Code:

//-------------------------------------------------
//  draw_led7seg - draw a 7-segment LCD
//-------------------------------------------------

void layout_element::component::draw_led7seg(bitmap_t &dest, const rectangle &bounds, int pattern)
{
	const rgb_t onpen = MAKE_ARGB(0xff,0xff,0xff,0xff);
	const rgb_t offpen = MAKE_ARGB(0xff,0x20,0x20,0x20);

	// sizes for computation
	int bmwidth = 250;
	int bmheight = 400;
	int segwidth = 40;
	int skewwidth = 40;

	// allocate a temporary bitmap for drawing
	bitmap_t *tempbitmap = global_alloc(bitmap_t(bmwidth + skewwidth, bmheight, BITMAP_FORMAT_ARGB32));
	bitmap_fill(tempbitmap, NULL, MAKE_ARGB(0xff,0x00,0x00,0x00));

	// top bar
	draw_segment_horizontal(*tempbitmap, 0 + 2*segwidth/3, bmwidth - 2*segwidth/3, 0 + segwidth/2, segwidth, (pattern & (1 << 0)) ? onpen : offpen);

	// top-right bar
	draw_segment_vertical(*tempbitmap, 0 + 2*segwidth/3, bmheight/2 - segwidth/3, bmwidth - segwidth/2, segwidth, (pattern & (1 << 1)) ? onpen : offpen);

	// bottom-right bar
	draw_segment_vertical(*tempbitmap, bmheight/2 + segwidth/3, bmheight - 2*segwidth/3, bmwidth - segwidth/2, segwidth, (pattern & (1 << 2)) ? onpen : offpen);

	// bottom bar
	draw_segment_horizontal(*tempbitmap, 0 + 2*segwidth/3, bmwidth - 2*segwidth/3, bmheight - segwidth/2, segwidth, (pattern & (1 << 3)) ? onpen : offpen);

	// bottom-left bar
	draw_segment_vertical(*tempbitmap, bmheight/2 + segwidth/3, bmheight - 2*segwidth/3, 0 + segwidth/2, segwidth, (pattern & (1 << 4)) ? onpen : offpen);

	// top-left bar
	draw_segment_vertical(*tempbitmap, 0 + 2*segwidth/3, bmheight/2 - segwidth/3, 0 + segwidth/2, segwidth, (pattern & (1 << 5)) ? onpen : offpen);

	// middle bar
	draw_segment_horizontal(*tempbitmap, 0 + 2*segwidth/3, bmwidth - 2*segwidth/3, bmheight/2, segwidth, (pattern & (1 << 6)) ? onpen : offpen);

	// apply skew
	apply_skew(*tempbitmap, 40);

	// decimal point
	draw_segment_decimal(*tempbitmap, bmwidth + segwidth/2, bmheight - segwidth/2, segwidth, (pattern & (1 << 7)) ? onpen : offpen);

	// resample to the target size
	render_resample_argb_bitmap_hq(dest.base, dest.rowpixels, dest.width, dest.height, tempbitmap, NULL, &m_color);

	global_free(tempbitmap);
}