Attachment 19487 Details for Bug 17971 – addblur.c convolves with ADD and paint_with_alpha

addblur.c convolves with ADD and paint_with_alpha

addblur.c (text/x-csrc), 4.75 KB, created by M Joonas Pihlaja on 2008-10-08 05:48:19 UTC

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Creator: M Joonas Pihlaja

Created: 2008-10-08 05:48:19 UTC

Size: 4.75 KB

patch

obsolete

>#define RUNME /*
>gcc -O0 -g -W -Wall -o `basename $0 .c` `pkg-config --cflags cairo` $0 `pkg-config --libs cairo`
>exit $?
>*/
>#include <stdio.h>
>#include <stdlib.h>
>#include <string.h>
>#include <cairo.h>
>#include <cairo-ps.h>
>#include <cairo-pdf.h>
>#include <cairo-svg.h>
>
>cairo_pattern_t *
>displaced_blend(cairo_t *cr,
>                cairo_pattern_t *pat,
>                double dx,
>                double dy)
>{
>        cairo_push_group(cr);
>        cairo_set_operator(cr, CAIRO_OPERATOR_ADD);
>
>        cairo_set_source(cr, pat);
>        cairo_paint_with_alpha(cr, 0.5);
>
>        cairo_translate(cr, dx, dy);
>        cairo_set_source(cr, pat);
>        cairo_paint_with_alpha(cr, 0.5);
>
>        cairo_pattern_destroy(pat);
>        return cairo_pop_group(cr);
>}
>
>cairo_pattern_t *
>blur_step(cairo_t *cr, cairo_pattern_t *pat)
>{
>        pat = displaced_blend(cr, pat, 0, 1);
>        pat = displaced_blend(cr, pat, 1, 0);
>        return pat;
>}
>
>cairo_pattern_t *
>blurred_pattern(cairo_t *cr, cairo_pattern_t *pat, unsigned n)
>{
>        while (n-->0) {
>                pat = blur_step(cr, pat);
>        }
>        return pat;
>}
>
>int
>main(int argc, char **argv)
>{
>        cairo_surface_t *surf = NULL;
>        cairo_t *cr = NULL;
>        cairo_pattern_t *pat = NULL;
>        int want_png = 0;
>        int num_blurs = 0;
>        int i;
>
>        /* Get a target surface. */
>        for (i=1; i<argc; i++) {
>                if (0 == strcmp(argv[i], "image")) {
>                        surf = cairo_image_surface_create(
>                                CAIRO_FORMAT_ARGB32,
>                                300, 300);
>                }
>                else if (0 == strcmp(argv[i], "ps2")) {
>                        surf = cairo_ps_surface_create(
>                                "out-addblur.ps",
>                                300, 300);
>                        cairo_ps_surface_restrict_to_level(
>                                surf, CAIRO_PS_LEVEL_2);
>                }
>                else if (0 == strcmp(argv[i], "ps3")) {
>                        surf = cairo_ps_surface_create(
>                                "out-addblur.ps",
>                                300, 300);
>                        cairo_ps_surface_restrict_to_level(
>                                surf, CAIRO_PS_LEVEL_3);
>                }
>                else if (0 == strcmp(argv[i], "svg1.1")) {
>                        surf = cairo_svg_surface_create(
>                                "out-addblur.svg",
>                                300, 300);
>                        cairo_svg_surface_restrict_to_version(
>                                surf,
>                                CAIRO_SVG_VERSION_1_1);
>                }
>                else if (0 == strcmp(argv[i], "svg1.2")) {
>                        surf = cairo_svg_surface_create(
>                                "out-addblur.svg",
>                                300, 300);
>                        cairo_svg_surface_restrict_to_version(
>                                surf,
>                                CAIRO_SVG_VERSION_1_2);
>                }
>                else if (0 == strcmp(argv[i], "pdf")) {
>                        surf = cairo_pdf_surface_create(
>                                "out-addblur.pdf",
>                                300, 300);
>                }
>                else if (0 == strcmp(argv[i], "png")) {
>                        want_png = 1;
>                }
>                else {
>                        num_blurs = atoi(argv[i]);
>                }
>        }
>        if (!surf) {
>                fprintf(stderr,
>                        "usage: [svg1.1|svg1.2|ps2|ps3|pdf|image] "
>                        "[png] [num_blurs]\n");
>                exit(1);
>        }
>
>        /* Create an empty context for the surface. */
>        cr = cairo_create(surf);
>        cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
>        cairo_paint(cr);
>
>        /* Create a pattern consisting of a red triangle. */
>        cairo_push_group(cr); {
>                cairo_set_source_rgba(cr, 1, 0, 0, 1);
>                cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
>                cairo_move_to(cr, 150, 250);
>                cairo_line_to(cr, 50, 50);
>                cairo_line_to(cr, 250, 50);
>                cairo_close_path(cr);
>                cairo_fill(cr);
>                pat = cairo_pop_group(cr);
>        }
>
>        /* Blur the pattern up. */
>        pat = blurred_pattern(cr, pat, num_blurs);
>
>        /* Paint the pattern. */
>        cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
>        cairo_set_source(cr, pat);
>        cairo_paint(cr);
>
>        /* Clean up. */
>        cairo_pattern_destroy(pat);
>        if (want_png) {
>                cairo_surface_write_to_png(surf, "out-addblur.png");
>        }
>        cairo_show_page(cr);
>        cairo_destroy(cr);
>        cairo_surface_destroy(surf);
>
>        return 0;
>}

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Attachments on bug 17971: 19487

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