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| author | scuri <scuri> | 2008-10-17 06:10:33 +0000 |
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| committer | scuri <scuri> | 2008-10-17 06:10:33 +0000 |
| commit | 7b52cc13af4e85f1ca2deb6b6c77de9c95ea0dcf (patch) | |
| tree | d0857278bde2eff784227c57dcaf930346ceb7ac /html/en/func/color.html | |
First commit - moving from LuaForge to SourceForge
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| -rw-r--r-- | html/en/func/color.html | 137 |
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diff --git a/html/en/func/color.html b/html/en/func/color.html new file mode 100644 index 0000000..9ec9928 --- /dev/null +++ b/html/en/func/color.html @@ -0,0 +1,137 @@ +<!doctype HTML PUBLIC "-//IETF//DTD HTML//EN"> +<html> + <head> + <title>Color Coding</title> + <meta http-equiv="Content-Language" content="en-us"> + <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> + <link rel="stylesheet" type="text/css" href="../../style.css"> + </head> + <body> + <h2 align="center">Color Coding</h2> + <p>The library's color system is RGB. In order to simplify some functions, a + compact representation was created for the 3 values. To make a conversion from + this representation to the 3 separate values and vice-versa, use functions + <b> <font>cdDecodeColor</font></b> + and <b> <font>cdEncodeColor</font></b>. + </p> + <p>When the canvas used does not support more than 8 bpp of color resolution, you + can use function <b> <font>Palette</font></b> to give the driver an idea of which + colors to prioritize. <b> <font>Palette</font>'s</b> behavior is driver dependent.</p> + <p>There are some predefined colors:</p> + <pre>CD_RED = (255, 0, 0) +CD_DARK_RED = (128, 0, 0) +CD_GREEN = (0 ,255, 0) +CD_DARK_GREEN = ( 0,128, 0) +CD_BLUE = ( 0, 0,255) +CD_DARK_BLUE = ( 0, 0,128) +CD_YELLOW = (255,255, 0) +CD_DARK_YELLOW = (128,128, 0) +CD_MAGENTA = (255, 0,255) +CD_DARK_MAGENTA = (128, 0,128) +CD_CYAN = ( 0,255,255) +CD_DARK_CYAN = ( 0,128,128) +CD_WHITE = (255,255,255) +CD_BLACK = ( 0, 0 , 0) +CD_DARK_GRAY = (128,128,128) +CD_GRAY = (192,192,192) +</pre> + <hr> + <pre class="function"><span class="mainFunction">long int <a name="cdEncodeColor">cdEncodeColor</a>(unsigned char red, unsigned char green, unsigned char blue) [in C]</span> + +cd.EncodeColor(r, g, b: number) -> (old_color: lightuserdata) [in Lua]</pre> + <p>Returns a codified triple (<em>r,g,b</em>) in a long integer such as <b><tt>0x00RRGGBB</tt></b>, + where <tt><b>RR</b> </tt>are the red components, <b><tt>GG</tt></b> are the + green ones and <b><tt>BB</tt></b> are the blue ones. The code is used in the CD + library to define colors. It can be used without an active canvas.</p> + <pre class="function"><span class="mainFunction">void <a name="cdDecodeColor">cdDecodeColor</a>(long int color, unsigned char *red, unsigned char *green, unsigned char *blue) [in C]</span> + +cd.DecodeColor(color: lightuserdata) -> (r, g, b: number) [in Lua]</pre> + <p>Returns the red, green and blue components of a color in the CD library. Can + be used without an active canvas.</p> + <pre class="function"><span class="mainFunction">long int <a name="cdEncodeAlpha">cdEncodeAlpha</a>(long int color, unsigned char alpha) [in C]</span> + +cd.EncodeAlpha(color: lightuserdata, alpha: number) -> (color: lightuserdata) [in Lua]</pre> + <p>Returns the given color coded with the alpha information. ATENTION: At the + moment only the Win32 with GDI+ and the IMAGERGB drivers support alpha + components in color coding. Se in <a href="../drv/gdiplus.html">Windows Using + GDI+ Base Driver</a> and <a href="../drv/irgb.html">IMAGERGB driver</a>. The + internal representation of the component is inverted, because the default value + must be 0 and opaque for backward compatibility, so you should use the <strong>cdDecodeAlpha</strong> + function ot the <strong>cdAlpha</strong> macro to retrieve the alpha component.</p> + <pre class="function"><span class="mainFunction">unsigned char <a name="cdDecodeAlpha">cdDecodeAlpha</a>(long int color) [in C]</span> + +cd.DecodeAlpha(color: lightuserdata) -> (a: number) [in Lua]</pre> + <p>Returns the alpha component of a color in the CD library. Can be used without + an active canvas. 0 is transparent, 255 is opaque.</p> + <pre class="function"><span class="mainFunction">unsigned char <a name="cdRed0">cdAlpha</a>(long int color); [in C]</span> + +cd.Alpha(color: lightuserdata) -> (r: number) [in Lua]</pre> + <p>Macro that returns the alpha component of a color in the CD library. Can be + used without an active canvas.</p> + <pre class="function"><span class="mainFunction">unsigned char <a name="cdRed">cdRed</a>(long int color); [in C]</span> + +cd.Red(color: lightuserdata) -> (r: number) [in Lua]</pre> + <p>Macro that returns the red component of a color in the CD library. Can be used + without an active canvas.</p> + <pre class="function"><span class="mainFunction">unsigned char <a name="cdGreen">cdGreen</a>(long int color); [in C]</span> + +cd.Green(color: lightuserdata) -> (g: number) [in Lua]</pre> + <p>Macro that returns the green component of a color in the CD library. Can be + used without an active canvas.</p> + <pre class="function"><span class="mainFunction">unsigned char <a name="cdBlue">cdBlue</a>(long int color); [in C]</span> + +cd.Blue(color: lightuserdata) -> (b: number) [in Lua]</pre> + <p>Macro that returns the blue component of a color in the CD library. Can be + used without an active canvas.</p> + <hr> + <pre class="function"><span class="mainFunction">int <a name="cdGetColorPlanes">cdCanvasGetColorPlanes</a>(cdCanvas* canvas); [in C]</span> + +canvas:GetColorPlanes() -> (bpp: number) [in Lua]</pre> + <p>Returns a given number, for instance <i>p</i>, which defines the number of + colors supported by the current device as <i>2<sup>p</sup></i>, representing + the number of bits by pixel. + </p> + <pre class="function"><span class="mainFunction">void <a name="cdPalette">cdCanvasPalette</a>(cdCanvas* canvas, int n, const long int *color, int mode); [in C]</span> + +canvas:Palette(palette: cdPalette; mode: number) [in Lua]</pre> + <p>In systems limited to 256 palette colors, this function aims at adding <b><tt> + n</tt></b> colors to the system's palette. In such systems, the colors + demanded forward or backward which are not in the palette are approximated to + the closest available color. The type can be <tt><b>CD_FORCE</b> </tt>or <b><tt>CD_POLITE</tt></b>. + <b><tt>CD_FORCE</tt></b> ignores the system colors and interface elements, + since the menus and dialogues may be in illegible colors, but there will be + more colors available. <tt><b>CD_POLITE</b></tt> is the recommended type. It + must always be used before drawing. It cannot be queried.</p> + +<h3><a name="Palette">Palette</a></h3> + + <pre class="function"><a name="cdCreatePalette">cd.CreatePalette</a>(size: number) -> (palette: cdPalette) [in Lua Only]</pre> + <p>Creates a palette.</p> + <pre class="function"><a name="cdKillPalette">cd.KillPalette</a>(palette: cdPalette) [in Lua Only]</pre> + <p>Destroys the created palette and liberates allocated memory. If this + function is not called in Lua, the garbage collector will call it.</p> + +<h3>Palette <a name="DataAccess">Data Access</a></h3> + + <p>Data access in Lua is done directly using the array access operators. The + colors can have their values checked or changed directly as if they + were Lua tables:</p> + + <pre>palette[index] = cd.EncodeColor(r, g, b) +count = #palette +... +color = palette[index] +r, g, b = cd.DecodeColor(color)</pre> + + <p>Notice that the type of value returned or received by + <font size="3">palette[index]</font><font size="2"> </font>is a + <font>lightuserdata</font>, the same type used with functions <b> + <font size="3">cdEncodeColor</font></b>, <b> + <font size="3">cdDecodeColor</font></b>, <b> + <font size="3">cdPixel</font></b>, <b> + <font size="3">cdForeground</font></b><font size="2"> + </font>and <b> <font size="3">cdBackground</font></b>.</p> + + + </body> +</html>
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