/**
* Apply the Scale4x 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 4x4 times the size of the source bitmap.
* \note This function operates like ::scale4x_buf() but the intermediate buffer is
* automatically allocated in the stack.
* \param void_dst Pointer at the first pixel of the destination bitmap.
* \param dst_slice Size in bytes of a destination bitmap row.
* \param void_src Pointer at the first pixel of the source bitmap.
* \param src_slice Size in bytes of a source bitmap row.
* \param pixel Bytes per pixel of the source and destination bitmap.
* \param width Horizontal size in pixels of the source bitmap.
* \param height Vertical size in pixels of the source bitmap.
*/
static void scale4x(void* void_dst, unsigned dst_slice, const void* void_src, unsigned src_slice, unsigned pixel, unsigned width, unsigned height)
{
unsigned mid_slice;
void* mid;
mid_slice = 2 * pixel * width; /* required space for 1 row buffer */
mid_slice = (mid_slice + 0x7) & ~0x7; /* align to 8 bytes */
#if HAVE_ALLOCA
mid = alloca(6 * mid_slice); /* allocate space for 6 row buffers */
assert(mid != 0); /* alloca should never fails */
#else
mid = malloc(6 * mid_slice); /* allocate space for 6 row buffers */
if (!mid)
return;
#endif
scale4x_buf(void_dst, dst_slice, mid, mid_slice, void_src, src_slice, pixel, width, height);
#if !HAVE_ALLOCA
free(mid);
#endif
}
/**
* Apply the Scale4x 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 4x4 times the size of the source bitmap.
* \note This function operates like ::scale4x_buf() but the intermediate buffer is
* automatically allocated in the stack.
* \param void_dst Pointer at the first pixel of the destination bitmap.
* \param dst_slice Size in bytes of a destination bitmap row.
* \param void_src Pointer at the first pixel of the source bitmap.
* \param src_slice Size in bytes of a source bitmap row.
* \param pixel Bytes per pixel of the source and destination bitmap.
* \param width Horizontal size in pixels of the source bitmap.
* \param height Vertical size in pixels of the source bitmap.
*/
static void scale4x(void* void_dst, unsigned dst_slice, const void* void_src, unsigned src_slice, unsigned pixel, unsigned width, unsigned height)
{
unsigned mid_slice;
void* mid;
mid_slice = 2 * pixel * width; /* required space for 1 row buffer */
mid_slice = (mid_slice + 0x7) & ~0x7; /* align to 8 bytes */
mid = alloca(6 * mid_slice); /* allocate space for 6 row buffers */
scale4x_buf(void_dst, dst_slice, mid, mid_slice, void_src, src_slice, pixel, width, height);
}
