Function scale2x

src/Engine/Scalers/scalebit.cpp:138–167

* Apply the Scale2x effect on a bitmap. * The destination bitmap is filled with the scaled version of the source bitmap. * The source bitmap isn't modified. * The destination bitmap must be manually allocated before calling the function, * note that the resulting size is exactly 2x2 times the size of the source bitmap. * \param void_dst Pointer at the first pixel of the destination bitmap. *

 * \param height Vertical size in pixels of the source bitmap.
 */
static void scale2x(void* void_dst, unsigned dst_slice, const void* void_src, unsigned src_slice, unsigned pixel, unsigned width, unsigned height)
{
	unsigned char* dst = (unsigned char*)void_dst;
	const unsigned char* src = (const unsigned char*)void_src;
	unsigned count;

	assert(height >= 2);

	count = height;

	stage_scale2x(SCDST(0), SCDST(1), SCSRC(0), SCSRC(0), SCSRC(1), pixel, width);

	dst = SCDST(2);

	count -= 2;
	while (count) {
		stage_scale2x(SCDST(0), SCDST(1), SCSRC(0), SCSRC(1), SCSRC(2), pixel, width);

		dst = SCDST(2);
		src = SCSRC(1);

		--count;
	}

	stage_scale2x(SCDST(0), SCDST(1), SCSRC(0), SCSRC(1), SCSRC(1), pixel, width);

#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
	scale2x_mmx_emms();
#endif
}

/**
 * Apply the Scale2x3 effect on a bitmap.