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marseymoji/waveflag.c

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