53c1b584fa
When waveflag.c was forked from behdad's repo one of the changes that was made effectively removed the ability to generate different sizes of flags, despite leaving the SIZE value in the source. Recently we needed to generate waved flags at a different power-of-two size, and found it no longer functioned as the original. These changes restore that while leaving the other changes in this forked version (mostly formatting changes) intact.
378 lines
12 KiB
C
378 lines
12 KiB
C
/*
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* Copyright 2014 Google Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Google contributors: Behdad Esfahbod, Roozbeh Pournader
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*/
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#include <cairo.h>
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#include <math.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <assert.h>
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#include <string.h>
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#define SCALE 8
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#define SIZE 128
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#define MARGIN (debug ? 24 : 0)
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static unsigned int debug;
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static cairo_path_t *wave_path_create(void) {
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cairo_surface_t *surface = cairo_image_surface_create(
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CAIRO_FORMAT_ARGB32, 0, 0);
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cairo_t *cr = cairo_create(surface);
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cairo_path_t *path;
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cairo_scale(cr, SIZE/128.*SCALE, SIZE/128.*SCALE);
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cairo_move_to(cr, 127.15, 81.52);
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cairo_rel_line_to(cr, -20.51, -66.94);
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cairo_rel_curve_to(cr, -0.61, -2, -2.22, -3.53, -4.25, -4.03);
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cairo_rel_curve_to(cr, -0.48, -0.12, -0.96, -0.18, -1.44, -0.18);
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cairo_rel_curve_to(cr, -1.56, 0, -3.07, 0.61, -4.2, 1.74);
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cairo_rel_curve_to(cr, -9.56, 9.56, -17.94, 11.38, -30.07, 11.38);
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cairo_rel_curve_to(cr, -3.68, 0, -7.72, -0.18, -11.99, -0.38);
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cairo_rel_curve_to(cr, -3.37, -0.15, -6.85, -0.31, -10.62, -0.4);
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cairo_rel_curve_to(cr, -0.66, -0.02, -1.31, -0.02, -1.95, -0.02);
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cairo_rel_curve_to(cr, -30.67, 0, -40.49, 18.56, -40.89, 19.35);
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cairo_rel_curve_to(cr, -0.52, 1.01, -0.73, 2.16, -0.62, 3.29);
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cairo_rel_line_to(cr, 6.72, 66.95);
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cairo_rel_curve_to(cr, 0.22, 2.22, 1.67, 4.13, 3.75, 4.95);
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cairo_rel_curve_to(cr, 0.7, 0.27, 1.43, 0.4, 2.16, 0.4);
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cairo_rel_curve_to(cr, 1.43, 0, 2.84, -0.52, 3.95, -1.5);
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cairo_rel_curve_to(cr, 0.1, -0.09, 12.42, -10.63, 32.13, -10.63);
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cairo_rel_curve_to(cr, 2.52, 0, 5.09, 0.17, 7.64, 0.51);
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cairo_rel_curve_to(cr, 9.27, 1.23, 16.03, 1.78, 21.95, 1.78);
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cairo_rel_curve_to(cr, 18.93, 0, 32.93, -6.1, 46.82, -20.38);
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cairo_curve_to(cr, 127.24, 85.85, 127.79, 83.59, 127.15, 81.52);
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cairo_close_path(cr);
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cairo_identity_matrix(cr);
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path = cairo_copy_path(cr);
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cairo_destroy(cr);
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cairo_surface_destroy(surface);
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return path;
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}
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static struct { double x, y; } mesh_points[] = {
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{ -1, 43},
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{ 30, -3},
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{ 77, 47},
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{104, 1},
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{130, 84},
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{100, 138},
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{ 45, 80},
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{ 7, 127},
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};
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#define M(i) mesh_points[i].x, mesh_points[i].y
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static cairo_pattern_t *wave_mesh_create(void) {
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cairo_pattern_t *pattern = cairo_pattern_create_mesh();
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cairo_matrix_t scale_matrix = {128./SIZE/SCALE, 0, 0, 128./SIZE/SCALE, 0, 0};
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cairo_pattern_set_matrix(pattern, &scale_matrix);
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cairo_mesh_pattern_begin_patch(pattern);
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cairo_mesh_pattern_line_to(pattern, M(0));
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cairo_mesh_pattern_curve_to(pattern, M(1), M(2), M(3));
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cairo_mesh_pattern_line_to(pattern, M(4));
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cairo_mesh_pattern_curve_to(pattern, M(5), M(6), M(7));
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cairo_mesh_pattern_set_corner_color_rgb(pattern, 0, 0, 0, .5);
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cairo_mesh_pattern_set_corner_color_rgb(pattern, 1, 1, 0, .5);
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cairo_mesh_pattern_set_corner_color_rgb(pattern, 2, 1, 1, .5);
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cairo_mesh_pattern_set_corner_color_rgb(pattern, 3, 0, 1, .5);
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cairo_mesh_pattern_end_patch(pattern);
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return pattern;
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}
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static cairo_surface_t *scale_flag(cairo_surface_t *flag) {
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unsigned int w = cairo_image_surface_get_width(flag);
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unsigned int h = cairo_image_surface_get_height(flag);
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cairo_surface_t *scaled = cairo_image_surface_create(
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CAIRO_FORMAT_ARGB32, 256, 256);
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cairo_t *cr = cairo_create(scaled);
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cairo_scale(cr, 256./w, 256./h);
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cairo_set_source_surface(cr, flag, 0, 0);
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cairo_pattern_set_filter(cairo_get_source(cr), CAIRO_FILTER_BEST);
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cairo_pattern_set_extend(cairo_get_source(cr), CAIRO_EXTEND_PAD);
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cairo_paint(cr);
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cairo_destroy(cr);
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return scaled;
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}
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static cairo_surface_t *load_scaled_flag(const char *filename) {
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cairo_surface_t *flag = cairo_image_surface_create_from_png(filename);
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cairo_surface_t *scaled = scale_flag(flag);
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cairo_surface_destroy(flag);
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return scaled;
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}
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/* Returns 65536 for luminosoty of 1.0. */
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static int luminosity(uint32_t pix) {
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unsigned int sr = (pix >> 16) & 0xFF;
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unsigned int sg = (pix >> 8) & 0xFF;
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unsigned int sb = pix & 0xFF;
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/* Apply gamma of 2.0 */
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sr = sr * sr;
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sg = sg * sg;
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sb = sb * sb;
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return (sr * 13933u /* 0.2126 * 65536 */ +
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sg * 46871u /* 0.7152 * 65536 */ +
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sb * 4731u /* 0.0722 * 65536 */) / (255*255);
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}
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/* Returns luminosity. Only miningul if pixel is opaque.
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* If pixel is not opaque, sets *transparent to 1. */
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static int luminosity_and_transparency(uint32_t pix, int *transparent) {
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if ((pix>>24) < 0xff) {
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*transparent = 1;
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return 0;
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}
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return luminosity(pix);
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}
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static double calculate_border_luminosity_and_transparency(
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cairo_surface_t *scaled_flag,
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int *transparent) {
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/* Some flags might have a border already. As such, skip
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* a few pixels on each side... */
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const unsigned int skip = 5;
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uint32_t *s = (uint32_t *) cairo_image_surface_get_data(scaled_flag);
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unsigned int width = cairo_image_surface_get_width(scaled_flag);
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unsigned int height = cairo_image_surface_get_height(scaled_flag);
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unsigned int sstride = cairo_image_surface_get_stride(scaled_flag) / 4;
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unsigned int luma = 0;
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unsigned int perimeter = (2 * ((width-2*skip) + (height-2*skip) - 2));
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assert(width > 2 * skip && height > 2 * skip);
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*transparent = 0;
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for (unsigned int x = skip; x < width - skip; x++)
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luma += luminosity_and_transparency(s[x], transparent);
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s += sstride;
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for (unsigned int y = 1 + skip; y < height - 1 - skip; y++) {
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luma += luminosity_and_transparency(s[skip], transparent);
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luma += luminosity_and_transparency(s[width - 1 - skip], transparent);
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s += sstride;
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}
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for (unsigned int x = skip; x < width - skip; x++)
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luma += luminosity_and_transparency(s[x], transparent);
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if (*transparent) {
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/* Flag is non-rectangular; eg. Nepal.
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* Don't draw a border. */
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return 0;
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}
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return luma / (65536. * perimeter);
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}
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static cairo_t *create_image(void) {
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cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
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(SIZE+2*MARGIN)*SCALE,
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(SIZE+2*MARGIN)*SCALE);
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cairo_t *cr = cairo_create(surface);
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cairo_surface_destroy(surface);
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return cr;
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}
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static cairo_surface_t *wave_surface_create(void) {
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cairo_t *cr = create_image();
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cairo_surface_t *surface = cairo_surface_reference(cairo_get_target(cr));
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cairo_pattern_t *mesh = wave_mesh_create();
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cairo_set_source(cr, mesh);
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cairo_paint(cr);
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cairo_pattern_destroy(mesh);
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cairo_destroy(cr);
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return surface;
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}
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static cairo_surface_t *texture_map(cairo_surface_t *src,
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cairo_surface_t *tex) {
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uint32_t *s = (uint32_t *) cairo_image_surface_get_data(src);
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unsigned int width = cairo_image_surface_get_width(src);
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unsigned int height = cairo_image_surface_get_height(src);
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unsigned int sstride = cairo_image_surface_get_stride(src) / 4;
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cairo_surface_t *dst = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
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width, height);
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uint32_t *d = (uint32_t *) cairo_image_surface_get_data(dst);
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unsigned int dstride = cairo_image_surface_get_stride(dst) / 4;
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uint32_t *t = (uint32_t *) cairo_image_surface_get_data(tex);
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unsigned int twidth = cairo_image_surface_get_width(tex);
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unsigned int theight = cairo_image_surface_get_height(tex);
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unsigned int tstride = cairo_image_surface_get_stride(tex) / 4;
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assert(twidth == 256 && theight == 256);
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for (unsigned int y = 0; y < height; y++) {
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for (unsigned int x = 0; x < width; x++) {
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unsigned int pix = s[x];
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unsigned int sa = pix >> 24;
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unsigned int sr = (pix >> 16) & 0xFF;
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unsigned int sg = (pix >> 8) & 0xFF;
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unsigned int sb = pix & 0xFF;
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if (sa == 0) {
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d[x] = 0;
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continue;
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}
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if (sa != 255) {
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sr = sr * 255 / sa;
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sg = sg * 255 / sa;
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sb = sb * 255 / sa;
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}
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assert(sb >= 127 && sb <= 129);
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d[x] = t[tstride * sg + sr];
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}
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s += sstride;
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d += dstride;
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}
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cairo_surface_mark_dirty(dst);
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return dst;
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}
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static void wave_flag(const char *input_filename, const char *output_filename) {
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static cairo_path_t *wave_path;
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static cairo_surface_t *wave_surface;
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double border_luminosity;
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int border_transparent;
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cairo_surface_t *scaled_flag, *waved_flag;
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cairo_t *cr;
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if (!wave_path)
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wave_path = wave_path_create();
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if (!wave_surface)
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wave_surface = wave_surface_create();
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printf("Processing %s\n", input_filename);
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scaled_flag = load_scaled_flag(input_filename);
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border_luminosity = calculate_border_luminosity_and_transparency(
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scaled_flag,
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&border_transparent);
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waved_flag = texture_map(wave_surface, scaled_flag);
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cairo_surface_destroy(scaled_flag);
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cr = create_image();
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cairo_translate(cr, SCALE * MARGIN, SCALE * MARGIN);
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cairo_set_source_surface(cr, waved_flag, 0, 0);
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cairo_append_path(cr, wave_path);
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if (!debug)
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cairo_clip_preserve(cr);
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cairo_paint(cr);
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if (!border_transparent) {
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double border_alpha = .5 + fabs(.5 - border_luminosity);
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double border_width = 3 * SCALE;
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double border_gray = (1 - border_luminosity) * border_alpha;
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if (debug)
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printf("Border: alpha %g width %g gray %g\n",
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border_alpha, border_width/SCALE, border_gray);
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cairo_save(cr);
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cairo_set_source_rgba(cr,
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border_gray, border_gray, border_gray, border_alpha);
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cairo_set_line_width(cr, border_width);
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if (!debug)
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cairo_set_operator(cr, CAIRO_OPERATOR_HSL_LUMINOSITY);
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cairo_stroke(cr);
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cairo_restore(cr);
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} else {
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printf("Transparent border\n");
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cairo_new_path(cr);
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}
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if (debug) {
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/* Draw mesh points. */
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cairo_save(cr);
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cairo_scale(cr, SIZE/128.*SCALE, SIZE/128.*SCALE);
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cairo_set_source_rgba(cr, .5, .0, .0, .9);
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cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
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for (unsigned int i = 0;
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i < sizeof(mesh_points) / sizeof(mesh_points[0]);
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i++) {
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cairo_move_to(cr, M(i));
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cairo_rel_line_to(cr, 0, 0);
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}
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cairo_set_line_width(cr, 2);
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cairo_stroke(cr);
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for (unsigned int i = 0; i < 4; i++) {
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cairo_move_to(cr, M(2*i));
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cairo_line_to(cr, M(2*i+1));
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cairo_move_to(cr, M(2*i));
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cairo_line_to(cr, M(7 - 2*i));
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}
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cairo_set_line_width(cr, .5);
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cairo_stroke(cr);
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cairo_restore(cr);
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}
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if (!debug) {
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/* Scale down, 2x at a time, to get best downscaling, because cairo's
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* downscaling is crap... :( */
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unsigned int scale = SCALE;
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while (scale > 1) {
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cairo_surface_t *old_surface, *new_surface;
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old_surface = cairo_surface_reference(cairo_get_target(cr));
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assert(scale % 2 == 0);
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scale /= 2;
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cairo_destroy(cr);
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new_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
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(SIZE+2*MARGIN)*scale,
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(SIZE+2*MARGIN)*scale);
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cr = cairo_create(new_surface);
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cairo_scale(cr, .5, .5);
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cairo_set_source_surface(cr, old_surface, 0, 0);
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cairo_paint(cr);
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cairo_surface_destroy(old_surface);
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cairo_surface_destroy(new_surface);
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}
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}
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cairo_surface_write_to_png(cairo_get_target(cr), output_filename);
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cairo_destroy(cr);
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}
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int main(int argc, char **argv) {
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if (argc != 3) {
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fprintf(stderr, "Usage: waveflag [-debug] in.png out.png\n");
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return 1;
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}
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if (!strcmp(argv[1], "-debug")) {
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debug = 1;
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argc--, argv++;
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}
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wave_flag(argv[1], argv[2]);
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return 0;
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}
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