/**
* art_rgb_affine: Affine transform source RGB image and composite.
* @dst: Destination image RGB buffer.
* @x0: Left coordinate of destination rectangle.
* @y0: Top coordinate of destination rectangle.
* @x1: Right coordinate of destination rectangle.
* @y1: Bottom coordinate of destination rectangle.
* @dst_rowstride: Rowstride of @dst buffer.
* @src: Source image RGB buffer.
* @src_width: Width of source image.
* @src_height: Height of source image.
* @src_rowstride: Rowstride of @src buffer.
* @affine: Affine transform.
* @level: Filter level.
* @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing.
*
* Affine transform the source image stored in @src, compositing over
* the area of destination image @dst specified by the rectangle
* (@x0, @y0) - (@x1, @y1). As usual in libart, the left and top edges
* of this rectangle are included, and the right and bottom edges are
* excluded.
*
* The @alphagamma parameter specifies that the alpha compositing be done
* in a gamma-corrected color space. Since the source image is opaque RGB,
* this argument only affects the edges. In the current implementation,
* it is ignored.
*
* The @level parameter specifies the speed/quality tradeoff of the
* image interpolation. Currently, only ART_FILTER_NEAREST is
* implemented.
**/
void
art_rgb_affine (art_u8 *dst, int x0, int y0, int x1, int y1, int dst_rowstride,
const art_u8 *src,
int src_width, int src_height, int src_rowstride,
const double affine[6],
ArtFilterLevel level,
ArtAlphaGamma *alphagamma)
{
/* Note: this is a slow implementation, and is missing all filter
levels other than NEAREST. It is here for clarity of presentation
and to establish the interface. */
int x, y;
double inv[6];
art_u8 *dst_p, *dst_linestart;
const art_u8 *src_p;
ArtPoint pt, src_pt;
int src_x, src_y;
int run_x0, run_x1;
dst_linestart = dst;
art_affine_invert (inv, affine);
for (y = y0; y < y1; y++)
{
pt.y = y + 0.5;
run_x0 = x0;
run_x1 = x1;
art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height,
inv);
dst_p = dst_linestart + (run_x0 - x0) * 3;
for (x = run_x0; x < run_x1; x++)
{
pt.x = x + 0.5;
art_affine_point (&src_pt, &pt, inv);
src_x = floor (src_pt.x);
src_y = floor (src_pt.y);
src_p = src + (src_y * src_rowstride) + src_x * 3;
dst_p[0] = src_p[0];
dst_p[1] = src_p[1];
dst_p[2] = src_p[2];
dst_p += 3;
}
dst_linestart += dst_rowstride;
}
}
static double
gnome_canvas_item_invoke_point (GnomeCanvasItem *item, double x, double y, int cx, int cy,
GnomeCanvasItem **actual_item)
{
#ifdef HACKISH_AFFINE
double i2w[6], w2c[6], i2c[6], c2i[6];
ArtPoint c, i;
#endif
#ifdef HACKISH_AFFINE
gnome_canvas_item_i2w_affine (item, i2w);
gnome_canvas_w2c_affine (item->canvas, w2c);
art_affine_multiply (i2c, i2w, w2c);
art_affine_invert (c2i, i2c);
c.x = cx;
c.y = cy;
art_affine_point (&i, &c, c2i);
x = i.x;
y = i.y;
#endif
return (* GNOME_CANVAS_ITEM_CLASS (GTK_OBJECT_GET_CLASS (item))->point) (
item, x, y, cx, cy, actual_item);
}
static void
test_affine (void) {
double src[6];
double dst[6];
double src2[6];
char str[128];
int i;
ArtPoint ps, pd, ptmp;
for (i = 0; i < 6; i++)
{
src[i] = (rand () * 2.0 / RAND_MAX) - 1.0;
src2[i] = (rand () * 2.0 / RAND_MAX) - 1.0;
}
#if 0
src[0] = 0.9999999;
src[1] = -0.000001;
src[2] = 0.000001;
src[3] = 0.9999999;
src[4] = 0;
src[5] = 0;
#if 1
src[0] = 0.98480775;
src[1] = -0.17364818;
src[2] = 0.17364818;
src[3] = 0.98480775;
#endif
src2[0] = 0.98480775;
src2[1] = -0.17364818;
src2[2] = 0.17364818;
src2[3] = 0.98480775;
#endif
ps.x = rand() * 100.0 / RAND_MAX;
ps.y = rand() * 100.0 / RAND_MAX;
art_affine_point (&pd, &ps, src);
art_affine_invert (dst, src);
art_affine_point (&ptmp, &pd, dst);
art_affine_to_string (str, src);
printf ("src = %s\n", str);
art_affine_to_string (str, dst);
printf ("dst = %s\n", str);
printf ("point (%g, %g) -> (%g, %g) -> (%g, %g)\n",
ps.x, ps.y, pd.x, pd.y, ptmp.x, ptmp.y);
art_affine_point (&ptmp, &ps, src);
art_affine_point (&pd, &ptmp, src2);
art_affine_to_string (str, src2);
printf ("src2 = %s\n", str);
printf ("point (%g, %g) -> (%g, %g) -> (%g, %g)\n",
ps.x, ps.y, ptmp.x, ptmp.y, pd.x, pd.y);
art_affine_multiply (dst, src, src2);
art_affine_to_string (str, dst);
printf ("dst = %s\n", str);
art_affine_point (&pd, &ps, dst);
printf ("point (%g, %g) -> (%g, %g)\n",
ps.x, ps.y, pd.x, pd.y);
}
