/usr/share/doc/libafterimage-dev/html/asgrad.html is in libafterimage-dev 2.2.11-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head><meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
<title>AFTERImage example 5: Gradient rendering</title>
<style type="text/css">
<!--
body {
margin-top: 5px;
background-repeat: repeat;
}
.copy {
margin-top: 10px;
margin-left: 4%;
margin-right: 4%;
}
.copy a:link, .copy a:visited {
color:#0FF;
text-decoration:none
}
.copy a:active, .copy a:hover {
color:#FC3;
text-decoration:underline
}
.copy2 {
margin-top: 10px;
margin-left: 0;
margin-right: 0;
}
.copy2 a:link, .copy a:visited {
color:#0FF;
text-decoration:none
}
.copy2 a:active, .copy a:hover {
color:#FC3;
text-decoration:underline
}
p.codeBlock {
background: #444444;
padding: 1em;
margin-left: 4em;
font-family:Tahoma, Arial, Verdana, Helvetica;
font-size:14px;
}
.container {
padding: -1em;
margin-left: 0em;
margin-right: 1em;
width: 100%;
background: #ccc;
border: 1px solid #000;
font-size:13px;
}
p.dense {
text-align: justify;
margin-top: 0em;
padding: 0em;
line-height: 110%;
}
p.sect_header
{
background-color: #dddddd;
color: #000000;
text-align: right;
font-size: 11pt;
}
p.refsect_header
{
text-align: left;
font-size: 14px;
line-height: 90%;
}
dl.dense {
padding: 0;
margin: 0;
font-size:14px;
}
ul.dense {
}
li.dense {
line-height: 110%;
}
dt.dense {
line-height: 110%;
text-align: bottom;
}
dd.dense {
font-size:14px;
}
-->
</style>
</head>
<body>
<A name="page_top"></A>
<A href="../../afterstep/html/preface.html">Preface</A> <A href="../../afterstep/html/visualselect.html">Introduction</A> <A href="../../afterstep/html/index.html">Main index</A> <A href="index.html">API Topic index</A> <A href="Glossary.html">API Glossary</A><p>
<h1>AFTERImage example 5: Gradient rendering</h1><font size=4>demonstrates rendering of multi point linear gradients</font><hr>
<A NAME="libAfterImage/tutorials/ASGrad"><UL><p class="sect_header"><B>libAfterImage/tutorials/ASGrad</B></p></A><LI><p class="refsect_header"><B>NAME</B></p>
<A NAME="ASGrad"></A><B>ASGrad</B><P class="dense"></P></LI><LI><p class="refsect_header"><B>SYNOPSIS</B></p><PRE><A href="afterimage.html#libAfterImage">libAfterImage</A> application for drawing multipoint linear gradients.
</PRE></LI><LI><p class="refsect_header"><B>DESCRIPTION</B></p><PRE>New steps described in this tutorial are :
<A href="asgrad.html#ASGrad">ASGrad</A>.1. Building <A href="asimagexml.html#gradient">gradient</A> specs.
<A href="asgrad.html#ASGrad">ASGrad</A>.2. Actual rendering <A href="asimagexml.html#gradient">gradient</A>.
</PRE></LI><LI><p class="refsect_header"><B>SEE ALSO</B></p><PRE>Tutorial 1: <A href="asview.html#ASView">ASView</A> - explanation of basic steps needed to use
<A href="afterimage.html#libAfterImage">libAfterImage</A> and some other simple things.
Tutorial 2: <A href="asscale.html#ASScale">ASScale</A> - image scaling basics.
Tutorial 3: <A href="astile.html#ASTile">ASTile</A> - image tiling and tinting.
Tutorial 4: <A href="asmerge.html#ASMerge">ASMerge</A> - scaling and blending of arbitrary number of
images.
</PRE></LI><LI><p class="refsect_header"><B>SOURCE</B></p><P class="dense"><div class="container"><PRE>
#include "../afterbase.h"
#include "../afterimage.h"
#include "common.h"
<A href="asvisual.html#ARGB32">ARGB32</A> default_colors[] = {
0xFF000000,
0xFF700070, /* violet */
0xFF0000FF, /* blue */
0xFF00FFFF, /* cyan */
0xFF00FF00,
0XFFFFFF00,
0XFF700000,
0XFFFF0000,
0xFF8080A0,
0xFFE0E0FF,
0xFFa0a0FF,
};
double default_offsets[] = { 0, 0.1, 0.15, 0.20, 0.35, 0.45, 0.55, 0.50,
0.65, 0.8, 1.0} ;
void usage()
{
printf( " Usage: asgrad -h | <geometry> <gradient_type> <color1> "
"<offset2> <color2> [ <offset3> <color3> ...]\n");
printf( " Where: geometry - size of the resulting image and window;\n");
printf( " gradient_type - One of the fiollowing values :\n");
printf( " 0 - linear left-to-right <A href="asimagexml.html#gradient">gradient</A>,\n");
printf( " 1 - diagonal lefttop-to-rightbottom,\n");
printf( " 2 - linear top-to-bottom <A href="asimagexml.html#gradient">gradient</A>,\n");
printf( " 3 - diagonal righttop-to-leftbottom;\n");
printf( " offset - floating point <A href="blender.html#value_scanlines()">value</A> from 0.0 to 1.0\n");
}
int main(int argc, char* argv[])
{
Display *dpy = NULL;
<A href="asvisual.html#ASVisual">ASVisual</A> *asv ;
int <A href="blender.html#screen_scanlines()">screen</A> = 0, depth = 0;
int dummy, geom_flags = 0;
unsigned int to_width, to_height ;
<A href="asimage.html#ASGradient">ASGradient</A> grad ;
<A href="asimage.html#ASGradient">ASGradient</A> default_grad = { 1, 11, &(default_colors[0]),
&(default_offsets[0])} ;
<A href="asimage.html#ASImage">ASImage</A> *grad_im = NULL;
/* see <A href="asview.html#ASView">ASView</A>.1 : */
set_application_name( argv[0] );
#<A href="asimagexml.html#if">if</A> (HAVE_AFTERBASE_FLAG==1)
set_output_threshold(OUTPUT_LEVEL_DEBUG);
#endif
if( argc > 1 )
{
if( strcmp( argv[1], "-h") == 0 )
{
usage();
return 0;
}
/* see <A href="asscale.html#ASScale">ASScale</A>.1 : */
geom_flags = XParseGeometry( argv[1], &dummy, &dummy,
&to_width, &to_height );
}else
usage();
memset( &grad, 0x00, sizeof(ASGradient));
#ifndef X_DISPLAY_MISSING
dpy = XOpenDisplay(NULL);
_XA_WM_DELETE_WINDOW = XInternAtom( dpy, "WM_DELETE_WINDOW", False);
<A href="blender.html#screen_scanlines()">screen</A> = DefaultScreen(dpy);
depth = DefaultDepth( dpy, <A href="blender.html#screen_scanlines()">screen</A> );
#endif
if( argc >= 5 )
{
int i = 2;
/* see <A href="asgrad.html#ASGrad">ASGrad</A>.1 : */
grad.type = atoi( argv[2] );
grad.npoints = 0 ;
grad.<A href="asimagexml.html#color">color</A> = safemalloc( ((argc-2)/2)*sizeof(ARGB32));
grad.offset = safemalloc( ((argc-2)/2)*sizeof(double));
while( ++i < argc )
{
if( grad.npoints > 0 )
{
if( i == argc-1 )
grad.offset[grad.npoints] = 1.0;
else
grad.offset[grad.npoints] = atof( argv[i] );
++i ;
}
/* see <A href="astile.html#ASTile">ASTile</A>.1 : */
if( parse_argb_color( argv[i], &(grad.<A href="asimagexml.html#color">color</A>[grad.npoints]))
!= argv[i] )
if( grad.offset[grad.npoints] >= 0. &&
grad.offset[grad.npoints]<= 1.0 )
grad.npoints++ ;
}
}else
{
grad = default_grad ;
if( argc >= 3 )
grad.type = atoi( argv[2] );
}
if( grad.npoints <= 0 )
{
show_error( " not enough <A href="asimagexml.html#gradient">gradient</A> points specified.");
return 1;
}
/* Making sure tiling geometry is sane : */
#ifndef X_DISPLAY_MISSING
if( !get_flags(geom_flags, WidthValue ) )
to_width = DisplayWidth(dpy, screen)*2/3 ;
if( !get_flags(geom_flags, HeightValue ) )
to_height = DisplayHeight(dpy, screen)*2/3 ;
#else
if( !get_flags(geom_flags, WidthValue ) )
to_width = 500 ;
if( !get_flags(geom_flags, HeightValue ) )
to_height = 500 ;
#endif
printf( "%s: rendering <A href="asimagexml.html#gradient">gradient</A> of type %d to %dx%d\n",
get_application_name(), grad.type&GRADIENT_TYPE_MASK,
to_width, to_height );
/* see <A href="asview.html#ASView">ASView</A>.3 : */
asv = create_asvisual( dpy, <A href="blender.html#screen_scanlines()">screen</A>, depth, NULL );
/* see <A href="asgrad.html#ASGrad">ASGrad</A>.2 : */
grad_im = make_gradient( asv, &grad, to_width, to_height,
SCL_DO_ALL,
#ifndef X_DISPLAY_MISSING
ASA_XImage,
#else
ASA_ASImage,
#endif
0, ASIMAGE_QUALITY_DEFAULT );
if( grad_im )
{
#ifndef X_DISPLAY_MISSING
/* see <A href="asview.html#ASView">ASView</A>.4 : */
Window w = create_top_level_window( asv,
DefaultRootWindow(dpy), 32, 32,
to_width, to_height, 1, 0, NULL,
"<A href="asimage.html#ASGradient">ASGradient</A>", NULL );
if( w != None )
{
Pixmap p ;
XMapRaised (dpy, w);
/* see <A href="asview.html#ASView">ASView</A>.5 : */
p = asimage2pixmap( asv, DefaultRootWindow(dpy), grad_im,
NULL, True );
destroy_asimage( &grad_im );
/* see common.c: set_window_background_and_free() : */
p = set_window_background_and_free( w, p );
/* see common.c: wait_closedown() : */
}
wait_closedown(w);
dpy = NULL;
#else
ASImage2file( grad_im, NULL, "asgrad.jpg", ASIT_Jpeg, NULL );
destroy_asimage( &grad_im );
#endif
}
return 0 ;
}
</PRE></div><br></p></LI>
<A NAME="libAfterImage/tutorials/ASGrad.1 [5.1]"><UL><p class="sect_header"><B>libAfterImage/tutorials/ASGrad.1 [5.1]</B></p></A><LI><p class="refsect_header"><B>SYNOPSIS</B></p><PRE>Step 1. Building <A href="asimagexml.html#gradient">gradient</A> specs.
</PRE></LI><LI><p class="refsect_header"><B>DESCRIPTION</B></p><PRE>Multipoint <A href="asimagexml.html#gradient">gradient</A> is defined as <A href="asimagexml.html#set">set</A> of <A href="asimagexml.html#color">color</A> values with offsets
of each point from the beginning of the <A href="asimagexml.html#gradient">gradient</A> on 1.0 <A href="asimagexml.html#scale">scale</A>.
Offsets of the first and last point in <A href="asimagexml.html#gradient">gradient</A> should always be
0. and 1.0 respectively, and other points should go in between.
For example 2 point <A href="asimagexml.html#gradient">gradient</A> will have always offsets 0. and 1.0,
3 points <A href="asimagexml.html#gradient">gradient</A> will have 0. for first <A href="asimagexml.html#color">color</A>, 1.0 for last <A href="asimagexml.html#color">color</A>
and anything in between for middle <A href="asimagexml.html#color">color</A>.
If offset is incorrect - point will be skipped at the time of
rendering.
There are 4 types of gradients supported : horizontal, top-left to
bottom-right diagonal, vertical and top-right to bottom-left diagonal.
Any cilindrical <A href="asimagexml.html#gradient">gradient</A> could be drawn as a 3 point <A href="asimagexml.html#gradient">gradient</A> with
border colors being the same.
Each <A href="asimagexml.html#gradient">gradient</A> point has ARGB <A href="asimagexml.html#color">color</A>, which means that it is possible
to <A href="asfont.html#draw_text()">draw</A> gradients in alpha channel as well as RGB. That makes for
semitransparent gradients, fading gradients, etc.
</PRE></LI><LI><p class="refsect_header"><B>EXAMPLE</B></p><PRE> grad.type = atoi( argv[2] );
grad.npoints = 0 ;
grad.<A href="asimagexml.html#color">color</A> = safemalloc( ((argc-2)/2)*sizeof(ARGB32));
grad.offset = safemalloc( ((argc-2)/2)*sizeof(double));
while( ++i < argc )
{
if( grad.npoints > 0 )
{
if( i == argc-1 )
grad.offset[grad.npoints] = 1.0;
else
grad.offset[grad.npoints] = atof( argv[i] );
++i ;
}
if( parse_argb_color( argv[i], &(grad.<A href="asimagexml.html#color">color</A>[grad.npoints]))
!= argv[i] )
if(grad.offset[grad.npoints] >= 0. &&
grad.offset[grad.npoints]<= 1.0 )
grad.npoints++ ;
}
</PRE></LI><LI><p class="refsect_header"><B>SEE ALSO</B></p><PRE><A href="asvisual.html#ARGB32">ARGB32</A>, parse_argb_color(), <A href="asimage.html#ASGradient">ASGradient</A>
</PRE></LI></UL>
<A NAME="libAfterImage/tutorials/ASGrad.2 [5.2]"><UL><p class="sect_header"><B>libAfterImage/tutorials/ASGrad.2 [5.2]</B></p></A><LI><p class="refsect_header"><B>SYNOPSIS</B></p><PRE>Step 2. Actually rendering <A href="asimagexml.html#gradient">gradient</A>.
</PRE></LI><LI><p class="refsect_header"><B>DESCRIPTION</B></p><PRE>All that is needed to <A href="asfont.html#draw_text()">draw</A> <A href="asimagexml.html#gradient">gradient</A> is to call make_gradient(),
passing pointer to <A href="asimage.html#ASGradient">ASGradient</A> structure, that describes <A href="asimagexml.html#gradient">gradient</A>.
Naturally size of the <A href="asimagexml.html#gradient">gradient</A> is needed too. Another parameter is
filter - that is a bit mask that allows one to <A href="asfont.html#draw_text()">draw</A> <A href="asimagexml.html#gradient">gradient</A> using only a
subset of the channels, represented by <A href="asimagexml.html#set">set</A> bits. SCL_DO_ALL means
that all 4 channels must be rendered.
make_gradient() creates <A href="asimage.html#ASImage">ASImage</A> of requested size and fills it with
<A href="asimagexml.html#gradient">gradient</A>. Special techinque based on error diffusion is utilized to
avoid sharp steps between grades of colors when limited range of
colors is used for <A href="asimagexml.html#gradient">gradient</A>.
</PRE></LI><LI><p class="refsect_header"><B>EXAMPLE</B></p><PRE> grad_im = make_gradient( asv, &grad, to_width, to_height,
SCL_DO_ALL,
ASA_XImage, 0, ASIMAGE_QUALITY_DEFAULT );
</PRE></LI><LI><p class="refsect_header"><B>NOTES</B></p><PRE>make_gradient(), ASScanline, <A href="asimage.html#ASImage">ASImage</A>.
</PRE></LI></UL></UL>
<p><A href="preface.html">Preface</A> <A href="visualselect.html">Introduction</A> <A href="index.html">Topic index</A> <A href="Glossary.html">Glossary</A> <A href="#page_top">Back to Top</A>
<hr>
<p><FONT face="Verdana, Arial, Helvetica, sans-serif" size="-2">AfterStep version 2.2.11</a></FONT>
</body>
</html>
|