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Don't put an off-by-one n_stops into cairo_shader_op_t. (_cairo_shader_op_find_color_stops): Put search for two color stops containing a given offset into its own function. Handle the case of before first and after last stop by returning the nearest stop twice. (_cairo_pattern_calc_color_at_pixel): Handle case of no color stops by returning a transparent pixel.
This commit is contained in:
Carl Worth
parent
8ad3ab22e4
commit
1a043bbf26
4 changed files with 131 additions and 64 deletions
11
ChangeLog
11
ChangeLog
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@ -1,3 +1,14 @@
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2005-02-25 Carl Worth <cworth@cworth.org>
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* src/cairo_pattern.c (_cairo_pattern_shader_init): Don't put an
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off-by-one n_stops into cairo_shader_op_t.
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(_cairo_shader_op_find_color_stops): Put search for two color
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stops containing a given offset into its own function. Handle the
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case of before first and after last stop by returning the nearest
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stop twice.
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(_cairo_pattern_calc_color_at_pixel): Handle case of no color
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stops by returning a transparent pixel.
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2005-02-24 Owen Taylor <otaylor@redhat.com>
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* src/cairo_win32_surface.c: Remove a left-over debug printf.
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@ -428,9 +428,7 @@ _cairo_pattern_shader_init (cairo_pattern_t *pattern,
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cairo_shader_op_t *op)
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{
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op->stops = pattern->stops;
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op->n_stops = pattern->n_stops - 1;
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op->min_offset = pattern->stops[0].offset;
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op->max_offset = pattern->stops[op->n_stops].offset;
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op->n_stops = pattern->n_stops;
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op->extend = pattern->extend;
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switch (pattern->filter) {
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@ -449,12 +447,52 @@ _cairo_pattern_shader_init (cairo_pattern_t *pattern,
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}
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}
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/* Find two color stops bounding the given offset. If the given offset
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* is before the first or after the last stop offset, the nearest
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* offset is returned twice.
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*/
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static void
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_cairo_shader_op_find_color_stops (cairo_shader_op_t *op,
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cairo_fixed_t offset,
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cairo_color_stop_t *stops[2])
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{
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int i;
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/* Before first stop. */
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if (offset <= op->stops[0].offset) {
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stops[0] = &op->stops[0];
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stops[1] = &op->stops[0];
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return;
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}
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/* Between two stops. */
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for (i = 0; i < op->n_stops - 1; i++) {
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if (offset <= op->stops[i + 1].offset) {
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stops[0] = &op->stops[i];
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stops[1] = &op->stops[i + 1];
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return;
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}
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}
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/* After last stop. */
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stops[0] = &op->stops[op->n_stops - 1];
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stops[1] = &op->stops[op->n_stops - 1];
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}
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void
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_cairo_pattern_calc_color_at_pixel (cairo_shader_op_t *op,
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cairo_fixed_t factor,
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int *pixel)
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{
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int i;
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cairo_color_stop_t *stops[2];
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/* A gradient with no color stops is just transparent. (It'd be
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smart to catch this no-op much higher in the stack too.)
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*/
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if (op->n_stops == 0) {
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*pixel = 0;
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return;
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}
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switch (op->extend) {
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case CAIRO_EXTEND_REPEAT:
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@ -472,35 +510,26 @@ _cairo_pattern_calc_color_at_pixel (cairo_shader_op_t *op,
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break;
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}
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if (factor < op->min_offset)
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factor = op->min_offset;
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else if (factor > op->max_offset)
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factor = op->max_offset;
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for (i = 0; i < op->n_stops; i++) {
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if (factor <= op->stops[i + 1].offset) {
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_cairo_shader_op_find_color_stops (op, factor, stops);
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/* take offset as new 0 of coordinate system */
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factor -= stops[0]->offset;
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/* take offset as new 0 of coordinate system */
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factor -= op->stops[i].offset;
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/* difference between two offsets == 0, abrubt change */
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if (stops[1]->scale)
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factor = ((cairo_fixed_48_16_t) factor << 16) /
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stops[1]->scale;
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op->shader_function (stops[0]->color_char,
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stops[1]->color_char,
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factor, pixel);
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/* difference between two offsets == 0, abrubt change */
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if (op->stops[i + 1].scale)
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factor = ((cairo_fixed_48_16_t) factor << 16) /
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op->stops[i + 1].scale;
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op->shader_function (op->stops[i].color_char,
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op->stops[i + 1].color_char,
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factor, pixel);
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/* multiply alpha */
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if (((unsigned char) (*pixel >> 24)) != 0xff) {
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*pixel = (*pixel & 0xff000000) |
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(MULTIPLY_COLORCOMP (*pixel >> 16, *pixel >> 24) << 16) |
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(MULTIPLY_COLORCOMP (*pixel >> 8, *pixel >> 24) << 8) |
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(MULTIPLY_COLORCOMP (*pixel >> 0, *pixel >> 24) << 0);
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}
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break;
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}
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/* multiply alpha */
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if (((unsigned char) (*pixel >> 24)) != 0xff) {
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*pixel = (*pixel & 0xff000000) |
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(MULTIPLY_COLORCOMP (*pixel >> 16, *pixel >> 24) << 16) |
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(MULTIPLY_COLORCOMP (*pixel >> 8, *pixel >> 24) << 8) |
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(MULTIPLY_COLORCOMP (*pixel >> 0, *pixel >> 24) << 0);
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}
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}
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@ -428,9 +428,7 @@ _cairo_pattern_shader_init (cairo_pattern_t *pattern,
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cairo_shader_op_t *op)
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{
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op->stops = pattern->stops;
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op->n_stops = pattern->n_stops - 1;
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op->min_offset = pattern->stops[0].offset;
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op->max_offset = pattern->stops[op->n_stops].offset;
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op->n_stops = pattern->n_stops;
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op->extend = pattern->extend;
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switch (pattern->filter) {
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@ -449,12 +447,52 @@ _cairo_pattern_shader_init (cairo_pattern_t *pattern,
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}
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}
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/* Find two color stops bounding the given offset. If the given offset
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* is before the first or after the last stop offset, the nearest
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* offset is returned twice.
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*/
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static void
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_cairo_shader_op_find_color_stops (cairo_shader_op_t *op,
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cairo_fixed_t offset,
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cairo_color_stop_t *stops[2])
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{
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int i;
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/* Before first stop. */
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if (offset <= op->stops[0].offset) {
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stops[0] = &op->stops[0];
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stops[1] = &op->stops[0];
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return;
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}
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/* Between two stops. */
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for (i = 0; i < op->n_stops - 1; i++) {
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if (offset <= op->stops[i + 1].offset) {
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stops[0] = &op->stops[i];
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stops[1] = &op->stops[i + 1];
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return;
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}
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}
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/* After last stop. */
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stops[0] = &op->stops[op->n_stops - 1];
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stops[1] = &op->stops[op->n_stops - 1];
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}
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void
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_cairo_pattern_calc_color_at_pixel (cairo_shader_op_t *op,
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cairo_fixed_t factor,
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int *pixel)
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{
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int i;
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cairo_color_stop_t *stops[2];
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/* A gradient with no color stops is just transparent. (It'd be
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smart to catch this no-op much higher in the stack too.)
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*/
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if (op->n_stops == 0) {
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*pixel = 0;
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return;
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}
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switch (op->extend) {
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case CAIRO_EXTEND_REPEAT:
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@ -472,35 +510,26 @@ _cairo_pattern_calc_color_at_pixel (cairo_shader_op_t *op,
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break;
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}
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if (factor < op->min_offset)
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factor = op->min_offset;
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else if (factor > op->max_offset)
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factor = op->max_offset;
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for (i = 0; i < op->n_stops; i++) {
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if (factor <= op->stops[i + 1].offset) {
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_cairo_shader_op_find_color_stops (op, factor, stops);
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/* take offset as new 0 of coordinate system */
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factor -= stops[0]->offset;
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/* take offset as new 0 of coordinate system */
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factor -= op->stops[i].offset;
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/* difference between two offsets == 0, abrubt change */
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if (stops[1]->scale)
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factor = ((cairo_fixed_48_16_t) factor << 16) /
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stops[1]->scale;
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op->shader_function (stops[0]->color_char,
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stops[1]->color_char,
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factor, pixel);
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/* difference between two offsets == 0, abrubt change */
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if (op->stops[i + 1].scale)
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factor = ((cairo_fixed_48_16_t) factor << 16) /
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op->stops[i + 1].scale;
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op->shader_function (op->stops[i].color_char,
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op->stops[i + 1].color_char,
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factor, pixel);
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/* multiply alpha */
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if (((unsigned char) (*pixel >> 24)) != 0xff) {
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*pixel = (*pixel & 0xff000000) |
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(MULTIPLY_COLORCOMP (*pixel >> 16, *pixel >> 24) << 16) |
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(MULTIPLY_COLORCOMP (*pixel >> 8, *pixel >> 24) << 8) |
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(MULTIPLY_COLORCOMP (*pixel >> 0, *pixel >> 24) << 0);
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}
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break;
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}
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/* multiply alpha */
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if (((unsigned char) (*pixel >> 24)) != 0xff) {
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*pixel = (*pixel & 0xff000000) |
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(MULTIPLY_COLORCOMP (*pixel >> 16, *pixel >> 24) << 16) |
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(MULTIPLY_COLORCOMP (*pixel >> 8, *pixel >> 24) << 8) |
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(MULTIPLY_COLORCOMP (*pixel >> 0, *pixel >> 24) << 0);
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}
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}
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@ -743,8 +743,6 @@ typedef void (*cairo_shader_function_t) (unsigned char *color0,
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typedef struct _cairo_shader_op {
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cairo_color_stop_t *stops;
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int n_stops;
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cairo_fixed_t min_offset;
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cairo_fixed_t max_offset;
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cairo_extend_t extend;
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cairo_shader_function_t shader_function;
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} cairo_shader_op_t;
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