--- /dev/null
+/*
+ *
+ * Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc.
+ * 2005 Lars Knoll & Zack Rusin, Trolltech
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Keith Packard not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission. Keith Packard makes no
+ * representations about the suitability of this software for any purpose. It
+ * is provided "as is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+ * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include "pixman-private.h"
+
+void
+_pixman_gradient_walker_init (pixman_gradient_walker_t *walker,
+ gradient_t * gradient,
+ pixman_repeat_t repeat)
+{
+ walker->num_stops = gradient->n_stops;
+ walker->stops = gradient->stops;
+ walker->left_x = 0;
+ walker->right_x = 0x10000;
+ walker->a_s = 0.0f;
+ walker->a_b = 0.0f;
+ walker->r_s = 0.0f;
+ walker->r_b = 0.0f;
+ walker->g_s = 0.0f;
+ walker->g_b = 0.0f;
+ walker->b_s = 0.0f;
+ walker->b_b = 0.0f;
+ walker->repeat = repeat;
+
+ walker->need_reset = TRUE;
+}
+
+static void
+gradient_walker_reset (pixman_gradient_walker_t *walker,
+ pixman_fixed_48_16_t pos)
+{
+ int32_t x, left_x, right_x;
+ pixman_color_t *left_c, *right_c;
+ int n, count = walker->num_stops;
+ pixman_gradient_stop_t *stops = walker->stops;
+ float la, lr, lg, lb;
+ float ra, rr, rg, rb;
+ float lx, rx;
+
+ if (walker->repeat == PIXMAN_REPEAT_NORMAL)
+ {
+ x = (int32_t)pos & 0xffff;
+ }
+ else if (walker->repeat == PIXMAN_REPEAT_REFLECT)
+ {
+ x = (int32_t)pos & 0xffff;
+ if ((int32_t)pos & 0x10000)
+ x = 0x10000 - x;
+ }
+ else
+ {
+ x = pos;
+ }
+
+ for (n = 0; n < count; n++)
+ {
+ if (x < stops[n].x)
+ break;
+ }
+
+ left_x = stops[n - 1].x;
+ left_c = &stops[n - 1].color;
+
+ right_x = stops[n].x;
+ right_c = &stops[n].color;
+
+ if (walker->repeat == PIXMAN_REPEAT_NORMAL)
+ {
+ left_x += (pos - x);
+ right_x += (pos - x);
+ }
+ else if (walker->repeat == PIXMAN_REPEAT_REFLECT)
+ {
+ if ((int32_t)pos & 0x10000)
+ {
+ pixman_color_t *tmp_c;
+ int32_t tmp_x;
+
+ tmp_x = 0x10000 - right_x;
+ right_x = 0x10000 - left_x;
+ left_x = tmp_x;
+
+ tmp_c = right_c;
+ right_c = left_c;
+ left_c = tmp_c;
+
+ x = 0x10000 - x;
+ }
+ left_x += (pos - x);
+ right_x += (pos - x);
+ }
+ else if (walker->repeat == PIXMAN_REPEAT_NONE)
+ {
+ if (n == 0)
+ right_c = left_c;
+ else if (n == count)
+ left_c = right_c;
+ }
+
+ /* The alpha channel is scaled to be in the [0, 255] interval,
+ * and the red/green/blue channels are scaled to be in [0, 1].
+ * This ensures that after premultiplication all channels will
+ * be in the [0, 255] interval.
+ */
+ la = (left_c->alpha * (1.0f/257.0f));
+ lr = (left_c->red * (1.0f/257.0f));
+ lg = (left_c->green * (1.0f/257.0f));
+ lb = (left_c->blue * (1.0f/257.0f));
+
+ ra = (right_c->alpha * (1.0f/257.0f));
+ rr = (right_c->red * (1.0f/257.0f));
+ rg = (right_c->green * (1.0f/257.0f));
+ rb = (right_c->blue * (1.0f/257.0f));
+
+ lx = left_x * (1.0f/65536.0f);
+ rx = right_x * (1.0f/65536.0f);
+
+ if (FLOAT_IS_ZERO (rx - lx) || left_x == INT32_MIN || right_x == INT32_MAX)
+ {
+ walker->a_s = walker->r_s = walker->g_s = walker->b_s = 0.0f;
+ walker->a_b = (la + ra) / 2.0f;
+ walker->r_b = (lr + rr) / 510.0f;
+ walker->g_b = (lg + rg) / 510.0f;
+ walker->b_b = (lb + rb) / 510.0f;
+ }
+ else
+ {
+ float w_rec = 1.0f / (rx - lx);
+
+ walker->a_b = (la * rx - ra * lx) * w_rec;
+ walker->r_b = (lr * rx - rr * lx) * w_rec * (1.0f/255.0f);
+ walker->g_b = (lg * rx - rg * lx) * w_rec * (1.0f/255.0f);
+ walker->b_b = (lb * rx - rb * lx) * w_rec * (1.0f/255.0f);
+
+ walker->a_s = (ra - la) * w_rec;
+ walker->r_s = (rr - lr) * w_rec * (1.0f/255.0f);
+ walker->g_s = (rg - lg) * w_rec * (1.0f/255.0f);
+ walker->b_s = (rb - lb) * w_rec * (1.0f/255.0f);
+ }
+
+ walker->left_x = left_x;
+ walker->right_x = right_x;
+
+ walker->need_reset = FALSE;
+}
+
+uint32_t
+_pixman_gradient_walker_pixel (pixman_gradient_walker_t *walker,
+ pixman_fixed_48_16_t x)
+{
+ float a, r, g, b;
+ uint8_t a8, r8, g8, b8;
+ uint32_t v;
+ float y;
+
+ if (walker->need_reset || x < walker->left_x || x >= walker->right_x)
+ gradient_walker_reset (walker, x);
+
+ y = x * (1.0f / 65536.0f);
+
+ a = walker->a_s * y + walker->a_b;
+ r = a * (walker->r_s * y + walker->r_b);
+ g = a * (walker->g_s * y + walker->g_b);
+ b = a * (walker->b_s * y + walker->b_b);
+
+ a8 = a + 0.5f;
+ r8 = r + 0.5f;
+ g8 = g + 0.5f;
+ b8 = b + 0.5f;
+
+ v = ((a8 << 24) & 0xff000000) |
+ ((r8 << 16) & 0x00ff0000) |
+ ((g8 << 8) & 0x0000ff00) |
+ ((b8 >> 0) & 0x000000ff);
+
+ return v;
+}
Code Review / kvmfornfv.git / blobdiff