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
*/
#include <cairo.h>
#include <libgen.h> // basename
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#define SCALE 8
#define SIZE 128
#define MARGIN (debug ? 4 : 0)
static unsigned int debug;
#define std_aspect (5./3.)
#define top 21
#define bot 128-top
#define B 21
#define C 4
static struct { double x, y; } mesh_points[] =
{
{ 1, top+C},
{ 43, top-B+C},
{ 85, top+B-C},
{127, top-C},
{127, bot-C},
{ 85, bot+B-C},
{ 43, bot-B+C},
{ 1, bot+C},
};
#define M(i) \
x_aspect (mesh_points[i].x, aspect), \
y_aspect (mesh_points[i].y, aspect)
static inline double x_aspect (double v, double aspect)
{
return aspect >= 1. ? v : (v - 64) * aspect + 64;
}
static inline double y_aspect (double v, double aspect)
{
return aspect <= 1. ? v : (v - 64) / aspect + 64;
}
static cairo_path_t *
wave_path_create (double aspect)
{
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, SIZE/128.*SCALE, SIZE/128.*SCALE);
cairo_line_to(cr, M(0));
cairo_curve_to(cr, M(1), M(2), M(3));
cairo_line_to(cr, M(4));
cairo_curve_to(cr, M(5), M(6), M(7));
cairo_close_path (cr);
cairo_identity_matrix (cr);
path = cairo_copy_path (cr);
cairo_destroy (cr);
cairo_surface_destroy (surface);
return path;
}
static cairo_pattern_t *
wave_mesh_create (double aspect, int alpha)
{
cairo_pattern_t *pattern = cairo_pattern_create_mesh();
cairo_matrix_t scale_matrix = {128./SIZE/SCALE, 0, 0, 128./SIZE/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));
if (alpha)
{
cairo_mesh_pattern_set_corner_color_rgba(pattern, 0, 1, 1, 1, .5);
cairo_mesh_pattern_set_corner_color_rgba(pattern, 1,.5,.5,.5, .5);
cairo_mesh_pattern_set_corner_color_rgba(pattern, 2, 0, 0, 0, .5);
cairo_mesh_pattern_set_corner_color_rgba(pattern, 3,.5,.5,.5, .5);
}
else
{
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, double *aspect)
{
cairo_surface_t *flag = cairo_image_surface_create_from_png (filename);
cairo_surface_t *scaled = scale_flag (flag);
*aspect = (double) cairo_image_surface_get_width (flag) /
(double) cairo_image_surface_get_height (flag);
cairo_surface_destroy (flag);
return scaled;
}
static int
is_transparent (uint32_t pix)
{
return ((pix>>24) < 0xff);
}
static int
border_is_transparent (cairo_surface_t *scaled_flag)
{
/* 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;
int transparent = 0;
assert (width > 2 * skip && height > 2 * skip);
for (unsigned int x = skip; x < width - skip; x++)
transparent |= is_transparent (s[x]);
s += sstride;
for (unsigned int y = 1 + skip; y < height - 1 - skip; y++)
{
transparent |= is_transparent (s[skip]);
transparent |= is_transparent (s[width - 1 - skip]);
s += sstride;
}
for (unsigned int x = skip; x < width - skip; x++)
transparent |= is_transparent (s[x]);
return transparent;
}
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 (double aspect)
{
cairo_t *cr = create_image ();
cairo_surface_t *surface = cairo_surface_reference (cairo_get_target (cr));
cairo_pattern_t *mesh = wave_mesh_create (aspect, 0);
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 *filename, const char *out_prefix)
{
static cairo_path_t *standard_wave_path;
static cairo_surface_t *standard_wave_surface;
cairo_path_t *wave_path;
cairo_surface_t *wave_surface;
int border_transparent;
char out[1000];
double aspect = 0;
cairo_surface_t *scaled_flag, *waved_flag;
cairo_t *cr;
if (debug) printf ("Processing %s\n", filename);
scaled_flag = load_scaled_flag (filename, &aspect);
aspect /= std_aspect;
aspect = sqrt (aspect); // Discount the effect
if (.9 <= aspect && aspect <= 1.1)
{
if (debug) printf ("Standard aspect ratio\n");
aspect = 1.;
}
if (aspect == 1.)
{
if (!standard_wave_path)
standard_wave_path = wave_path_create (aspect);
if (!standard_wave_surface)
standard_wave_surface = wave_surface_create (aspect);
wave_path = standard_wave_path;
wave_surface = standard_wave_surface;
}
else
{
wave_path = wave_path_create (aspect);
wave_surface = wave_surface_create (aspect);
}
border_transparent = border_is_transparent (scaled_flag);
waved_flag = texture_map (wave_surface, scaled_flag);
cairo_surface_destroy (scaled_flag);
cr = create_image ();
cairo_translate (cr, SCALE * MARGIN, SCALE * MARGIN);
// Paint waved flag
cairo_set_source_surface (cr, waved_flag, 0, 0);
cairo_append_path (cr, wave_path);
if (!debug)
cairo_clip_preserve (cr);
cairo_paint (cr);
// Paint border
if (!border_transparent)
{
double border_alpha = .2;
double border_width = 4 * SCALE;
double border_gray = 0x42/255.;
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_alpha,
border_gray * border_alpha,
border_gray * border_alpha,
border_alpha);
cairo_set_line_width (cr, 2*border_width);
if (!debug)
cairo_set_operator (cr, CAIRO_OPERATOR_MULTIPLY);
cairo_stroke (cr);
cairo_restore (cr);
}
else
{
if (debug) printf ("Transparent border\n");
cairo_new_path (cr);
}
// Paint shade gradient
{
cairo_pattern_t *gradient = wave_mesh_create (aspect, 1);
cairo_pattern_t *w = cairo_pattern_create_for_surface (waved_flag);
cairo_save (cr);
cairo_set_source (cr, gradient);
cairo_set_operator (cr, CAIRO_OPERATOR_SOFT_LIGHT);
cairo_mask (cr, w);
cairo_restore (cr);
cairo_pattern_destroy (w);
}
if (debug)
{
/* Draw mesh points. */
cairo_save (cr);
cairo_scale (cr, SIZE/128.*SCALE, SIZE/128.*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);
}
}
*out = '\0';
strcat (out, out_prefix);
// diff from upstream. we call this a bit differently, filename might not be in cwd.
// basename wants a non-const argument. The problem here is paths that end in a
// slash, POSIX basename removes them while GNU just returns a pointer to that
// slash. Since this is supposed to be a filename such input is illegal for us.
// We're already not checking for overflow of the output buffer anyway...
strcat (out, basename((char *) filename));
cairo_surface_write_to_png (cairo_get_target (cr), out);
cairo_destroy (cr);
if (wave_path != standard_wave_path)
cairo_path_destroy (wave_path);
if (wave_surface != standard_wave_surface)
cairo_surface_destroy (wave_surface);
}
int
main (int argc, char **argv)
{
const char *out_prefix;
if (argc < 3)
{
fprintf (stderr, "Usage: waveflag [-debug] out-prefix [in.png]...\n");
return 1;
}
if (!strcmp (argv[1], "-debug"))
{
debug = 1;
argc--, argv++;
}
out_prefix = argv[1];
argc--, argv++;
for (argc--, argv++; argc; argc--, argv++)
wave_flag (*argv, out_prefix);
return 0;
}