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gds-render
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Color palette: Finish implementation 

Color palette can now be loaded from a resource containing hexadecimal
RGB values.
This commit is contained in:
Mario Hüttel 2019-06-13 21:44:09 +02:00
parent e847e691bd
commit dfadaa241e
1 changed files with 108 additions and 0 deletions
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108
layer/color-palette.c
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@ -40,6 +40,40 @@ struct _ColorPalette {
G_DEFINE_TYPE(ColorPalette, color_palette, G_TYPE_OBJECT)
/**
* @brief Return the number of non empty lines in array
*
* This function returns the number of non empty lines in an
* array. The scanning is either terminated by the given length
* or if a \0 terminator is found.
*
* @param[in] data Array to count lines in
* @param[in] length Length of \p data
* @return < 0: Error, >=0: Lines
*/
static int count_non_empty_lines_in_array(const char *data, size_t length)
{
unsigned int idx;
int non_empty_lines;
char last_char = '\n';
if (!data)
return -1;
/* Count each '\n' as a new line if it is not directly preceded by another '\n' */
for (idx = 0; idx < length && data[idx]; idx++) {
if (data[idx] == '\n' && last_char != '\n')
non_empty_lines++;
last_char = data[idx];
}
/* Count the last line in case the data does not end with a '\n' */
if (data[idx-1] != '\n')
non_empty_lines++;
return non_empty_lines;
}
/**
* @brief color_palette_fill_with_resource
* @param palette
@ -49,8 +83,16 @@ G_DEFINE_TYPE(ColorPalette, color_palette, G_TYPE_OBJECT)
static int color_palette_fill_with_resource(ColorPalette *palette, char *resource_name)
{
GBytes *data;
char line[10];
int line_idx;
unsigned int color_idx;
int idx;
const char *char_array;
gsize byte_count;
int lines;
GRegex *regex;
GMatchInfo *mi;
char *match;
if (!palette || !resource_name)
return -1;
@ -65,9 +107,75 @@ static int color_palette_fill_with_resource(ColorPalette *palette, char *resourc
if (!char_array || !byte_count)
goto ret_unref;
/* Get maximum lenght of color palette, assuming all entries are valid */
lines = count_non_empty_lines_in_array(char_array, byte_count);
if (lines <= 0)
goto ret_unref;
palette->color_array = (GdkRGBA *)malloc(sizeof(GdkRGBA) * (unsigned int)lines);
/* Setup regex for hexadecimal RGB colors like 'A0CB3F' */
regex = g_regex_new("^(?<red>[0-9A-Fa-f][0-9A-Fa-f])(?<green>[0-9A-Fa-f][0-9A-Fa-f])(?<blue>[0-9A-Fa-f][0-9A-Fa-f])$", 0, 0, NULL);
/* Reset line */
line_idx = 0;
line[0] = '\0';
/* Set color index */
color_idx = 0;
/* interate over lines and match */
for (idx = 0 ; idx < byte_count; idx++) {
/* Fillup line. */
line[line_idx] = char_array[idx];
/* If end of line/string is reached, process */
if (line[line_idx] == '\n' || line[line_idx] == '\0') {
line[line_idx] = '\0';
/* Match the line */
g_regex_match(regex, line, 0, &mi);
if (g_match_info_matches(mi) && color_idx < lines) {
match = g_match_info_fetch_named(mi, "red");
palette->color_array[color_idx].red = (double)g_ascii_strtoll(match, NULL, 16) / 255.0;
g_free(match);
match = g_match_info_fetch_named(mi, "green");
palette->color_array[color_idx].green = (double)g_ascii_strtoll(match, NULL, 16) / 255.0;
g_free(match);
match = g_match_info_fetch_named(mi, "blue");
palette->color_array[color_idx].blue = (double)g_ascii_strtoll(match, NULL, 16) / 255.0;
g_free(match);
/* Only RGB supported so far. Fix alpha channel to 1.0 */
palette->color_array[color_idx].alpha = 1.0;
color_idx++;
}
g_match_info_free(mi);
/* End of string */
if (char_array[idx] == '\0')
break;
line_idx = 0;
continue;
}
/* increment line index. If end is reached write all bytes to the line end
* line is longer than required for parsing. This ensures, that everything works as expected
*/
line_idx += (line_idx < sizeof(line)-1 ? 1 : 0);
}
/* Data read; Shrink array in case of invalid lines */
palette->color_array = realloc(palette->color_array, (size_t)color_idx * sizeof(GdkRGBA));
palette->color_array_length = color_idx;
g_regex_unref(regex);
ret_unref:
g_bytes_unref(data);