177 lines
7.4 KiB
Plaintext
177 lines
7.4 KiB
Plaintext
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colors.c / colors.h
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To convert in-game player name colors to html display.
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References used:
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http://www.rapidtables.com/convert/color/hsl-to-rgb.htm
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http://www.rapidtables.com/convert/color/rgb-to-hsl.htm
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https://gitlab.com/xonotic/xonstat/blob/master/xonstat/util.py
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Overview:
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This component is slightly based on util.py of XonStats, but the only
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functionality needed is coloring the player's names. Since C programming
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language does not have standard libraries for color model conversions and
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regex, some functionality had to be self written. The function of interest
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is:
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def html_colors(qstr='', limit=None):
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This component uses purely C standard library.
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Advanced string manipulations such as replace and concatenation are
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avoided. Instead, strings are printed in parts across functions.
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There is only one instance of dynamic memory allocation.
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void print_plname(const char *)
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It both allocates, near the start, and frees memory at the end.
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darkplaces Player Names & Colors
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Players can add color themes to their names. They're expressed either
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decimal or hexidecimal.
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The decimal format follows
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A character '^' that is not displayed, followed by a single digit
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between 0 and 9.
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The hexidecimal format follows
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A string '^x' that is not displayed, followed by 3 digits between
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0 - 0xF.
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Python Regex to C Translation
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The snippets from the original python code:
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_all_colors = re.compile(r'\^(\d|x[\dA-Fa-f]{3})')
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_dec_colors = re.compile(r'\^(\d)')
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_hex_colors = re.compile(r'\^x([\dA-Fa-f])([\dA-Fa-f])([\dA-Fa-f])')
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_dec_spans = [
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"<span style='color:rgb(128,128,128)'>",
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"<span style='color:rgb(255,0,0)'>",
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"<span style='color:rgb(51,255,0)'>",
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"<span style='color:rgb(255,255,0)'>",
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"<span style='color:rgb(51,102,255)'>",
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"<span style='color:rgb(51,255,255)'>",
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"<span style='color:rgb(255,51,102)'>",
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"<span style='color:rgb(255,255,255)'>",
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"<span style='color:rgb(153,153,153)'>",
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"<span style='color:rgb(128,128,128)'>"
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]
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...
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def html_colors(qstr='', limit=None):
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...
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html = _dec_colors.sub(lambda match: _dec_spans[int(match.group(1))],
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qstr)
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html = _hex_colors.sub(hex_repl, html)
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...
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html = _dec_colors.sub(lambda match: _dec_spans[int(match.group(1))], qstr)
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The character following a '^' is treated as an index to the array
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'_dec_spans'. The corresponding element in '_dec_spans' replaces the
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character '^' and the following digit in the string 'qstr'.
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html = _hex_colors.sub(hex_repl, html)
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The output of function 'hex_repl' replaces matching strings in html-
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'^x' followed by 3 hexadecimal digits. The function 'hex_repl' has more
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to do with the algorithms of color model conversions than it has to do
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with regex rules.
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The control flow to output similar results to the regex substitutions is
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in the function
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static void b(char * const str);
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Unlike the python counterparts, it segments the player name into tokens and
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prints strings also other strings instead of the sequences not intended to
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be displayed.
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Function Walkthrough
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Sorted by caller to callee.
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void print_plname(const char *)
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const char * parameter is the player's name. It is used as a basis for
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the variable 'copy'. 'copy' will always be the shorter character string.
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This is function is intended to be used by the client file.
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This function unconditionally allocates memory (calloc) and frees it at
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the end.
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By itself, it only removes extraneous instances of the character '^'.
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It then calls the function
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static void b(char * const)
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where actual output occurs.
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static void b(char * const)
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const char * parameter is the player's name. The data pointed at by the
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pointer is altered by function 'strtok', but the pointer itself is
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never changed. Abstractly, fragments of the player's name are treated
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as a command to print specific strings.
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This function iterates once through the player's name. 'strtok'
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segments the player's name; sequences between and not including '^'s
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are treated as substrings. The first character of the substring is
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checked for a digit inclusively between 0 and 9 for a decimal color
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code. Exclusively or, checked for an 'x' and a numerical sequence
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afterwards for a hexidecimal color code. If the substring does not have
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either, it is printed like an ordinary string.
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This function may not be adequate when a player's name intentionally
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contains '^'.
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static void hexspan(const char *)
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const char * parameter is ideally a sequence of 3 hexidecimal digits.
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Actually it is the entire substring from the callee. The first 3
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elements are of interest as 3 separate single digit numerical values
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and are explicitly separated to prevent function 'strtol' from
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interpreting them as multidigit numbers. These 3 elements are rgb
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values from the game engine.
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Xonotic represents RGB values as a sequence of three digits 0 - 0xF.
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Before conversion is to be done, they must be multiplied by 0xF so the
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full range of values for RGB, 0 - 255 can be represented.
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This function prints the an html span tag.
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This function will first convert rgb to hsl to check if the colors are
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too dark for the web page, and if so brighten up the colors then
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reconvert to rgb.
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static void decspan(const int)
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const int parameter is a digit, the range being [0, 9].
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This function is straightforward. It will print an html tag
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corresponding to the const int parameter.
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void hsl2rgb(struct Rgb *, const struct Hls const *)
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First parameter, 'struct Rgb *' is the result of the conversion. It
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does not need to be initialized.
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Second parameter, 'const struct Hls const *' is the values and color
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model to convert from and because, it must be initialized.
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The math referenced from:
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http://www.rapidtables.com/convert/color/hsl-to-rgb.htm
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The implemenation deviates at the last 3 lines of code where the
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results are finalized and placed in the output. The webpage does not
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mention that rounding up is necessary. However it is, otherwise the
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nonzero rgb values for the following colors
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Silver (0<>,0%,75%)
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Gray (0<>,0%,50%)
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Maroon (0<>,100%,25%)
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Olive (60<36>,100%,25%)
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Green (120<32>,100%,25%)
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Purple (300<30>,100%,25%)
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Teal (180<38>,100%,25%)
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Navy (240<34>,100%,25%)
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will be off by one.
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void rgb2hsl(struct Hls *, const struct Rgb const *)
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First parameter, 'struct Hls *' is the result of the conversion. It
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does not need to be initialized.
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Second parameter, 'const struct Rgb const *' is the values and color
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model to convert from and because, it must be initialized.
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The math referenced from:
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http://www.rapidtables.com/convert/color/rgb-to-hsl.htm
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The implementation deviates when calculating hue, when Cmax is R'.
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Instead of modulo, there is a summation by 6 when G' is less than B'.
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