imagesetpixel
(PHP 4, PHP 5, PHP 7, PHP 8)
imagesetpixel — 点を生成する
説明
imagesetpixel() は、指定した座標にピクセルを描画します。
パラメータ
imageimagecreatetruecolor()のような画像作成関数が返す GdImage オブジェクト。
x-
x 座標。
y-
y 座標。
color-
imagecolorallocate() で作成された色識別子。
変更履歴
| バージョン | 説明 |
|---|---|
| 8.0.0 |
image は、
GdImage
クラスのインスタンスを期待するようになりました。
これより前のバージョンでは、有効な gd resource が期待されていました。
|
例
例1 imagesetpixel() の例
A random drawing that ends with a regular picture.
<?php
$x = 200;
$y = 200;
$gd = imagecreatetruecolor($x, $y);
$corners[0] = array('x' => 100, 'y' => 10);
$corners[1] = array('x' => 0, 'y' => 190);
$corners[2] = array('x' => 200, 'y' => 190);
$red = imagecolorallocate($gd, 255, 0, 0);
for ($i = 0; $i < 100000; $i++) {
imagesetpixel($gd, round($x), round($y), $red);
$a = rand(0, 2);
$x = ($x + $corners[$a]['x']) / 2;
$y = ($y + $corners[$a]['y']) / 2;
}
header('Content-Type: image/png');
imagepng($gd);
?>上の例の出力は、 たとえば以下のようになります。
参考
- imagecreatetruecolor() - TrueColor イメージを新規に作成する
- imagecolorallocate() - 画像で使用する色を作成する
- imagecolorat() - ピクセルの色のインデックスを取得する
＋add a note
User Contributed Notes 24 notes
d [AT] sprid [DOT] de ¶
19 years ago
This code does generate a RGB-cube (with or without borders). Because its only rendering the visible pixels its clearly fast (approx 1 up to 2 seconds). With changing the $order-variable you can see the cube from different perspectives. Entering double or tribble values (like rrg or ggg) will give you other specs of single channels. Send any sugestions to my email.
<?php
$borders = true;
$order = 'rgb';
set_time_limit(0);
$img = imageCreateTrueColor(510, 510);
$bg = imageColorAllocate($img, 255, 255, 255);
$black = imageColorAllocate($img, 255, 255, 255);
for ($r=0; $r<256; $r++) {
for ($g=0; $g<256; $g++) {
for ($b=0; $b<256; $b++) {
$rN = ${$order{0}};
$gN = ${$order{1}};
$bN = ${$order{2}};
$col = imageColorAllocate($img, $rN, $gN, $bN);
imagesetpixel($img, $b+($r*0.5)+(255/4), $g+($r*0.5)+(255/4), $col);
if ($r < 255 && $g > 0) break;
}
}
if ($borders) {
imagesetpixel($img, ($r*0.5+(255/4)), ($r*0.5)+(255/4), $black);
imagesetpixel($img, ($r*0.5)+255+(255/4), ($r*0.5)+(255/4), $black);
imagesetpixel($img, ($r*0.5)+(255/4), ($r*0.5)+255+(255/4), $black);
}
}
if ($borders) {
imageline($img, 255/4, 255/4, 255+(255/4), 255/4, $black);
imageline($img, 255/4, 255/4, 255/4, 255+(255/4), $black);
imageline($img, 255*0.5+(255/4), 255*0.5+(255/4), 255*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), $black);
imageline($img, 255*0.5+(255/4), 255*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), 255*0.5+(255/4), $black);
imageline($img, 255*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), $black);
imageline($img, 255*0.5 + 509*0.5+(255/4), 255*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), 255*0.5 + 509*0.5+(255/4), $black);
}
header("Content-Type: image/png");
imagepng($img);
imagedestroy($img);
?>
guy032 at gmail dot com ¶
12 years ago
making images with white (or close to white) background transprent
<?
function FloodFill($im, $x, $y)
{
$rgb = imagecolorat($im, $x, $y);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
$counter=0;
$counter2=0;
if($r >= 245){ $counter++;}
if($g >= 245){ $counter++;}
if($b >= 245){ $counter++;}
if($r >= 240){ $counter2++;}
if($g >= 240){ $counter2++;}
if($b >= 240){ $counter2++;}
if($counter >= 1 && $counter2 == 3){
$background = imagecolorallocate($im, 180, 0, 255);
imagesetpixel($im, $x, $y, $background);
FloodFill ($im, $x, $y+1);
FloodFill ($im, $x+1, $y);
FloodFill ($im, $x, $y-1);
}
}
$src = $_GET["src"];
$im = imagecreatefromjpeg($src);
// Draw border
$border = imagecolorallocate($im, 180, 0, 255);
drawBorder($im, $border, 1);
// Draw a border
function drawBorder($im, $color, $thickness = 1)
{
$x1 = 0;
$y1 = 0;
$x2 = ImageSX($im) - 1;
$y2 = ImageSY($im) - 1;
for($i = 0; $i < $thickness; $i++)
{
ImageRectangle($im, $x1++, $y1++, $x2--, $y2--, $color);
}
}
$rgb = imagecolorat($im, 0, 0);
FloodFill($im, 0, 0);
$color = imagecolorallocate($im, 180, 0, 255);
imagecolortransparent($im, $color);
header("Content-type: image/png");
imagepng($im);
imagedestroy($im);
?>
odin<spam inside(C)>dtdm.org ¶
20 years ago
Just a simple implementation of the Bresenham algorythm (educational purpose....)
You can find more about this and many other tutorials for gfx there: http://brand107.home.comcast.net/pc-gpe/
<?php
/****************************************************
Bresenham Line Algorythm PHP/GD implementation
****************************************************/
function line($im,$x1,$y1,$x2,$y2,$color){
$deltax=abs($x2-$x1);
$deltay=abs($y2-$y1);
if ($deltax>$deltay) {
$numpixels=$deltax+1;
$d=(2*$deltay)-$deltax;
$dinc1=$deltay << 1; $dinc2=($deltay-$deltax) << 1;
$xinc1=1; $xinc2=1;
$yinc1=0; $yinc2=1;
} else {
$numpixels=$deltay+1;
$d=(2*$deltax)-$deltay;
$dinc1=$deltax << 1; $dinc2=($deltax-$deltay)<<1;
$xinc1=0; $xinc2=1;
$yinc1=1; $yinc2=1;
}
if ($x1>$x2) {
$xinc1=-$xinc1;
$xinc2=-$xinc2;
}
if ($y1>$y2) {
$yinc1=-$yinc1;
$yinc2=-$yinc2;
}
$x=$x1;
$y=$y1;
for ($i=0;$i<$numpixels;$i++) {
imagesetpixel($im,$x,$y,$color);
if ($d<0) {
$d+=$dinc1;
$x+=$xinc1;
$y+=$yinc1;
} else {
$d+=$dinc2;
$x+=$xinc2;
$y+=$yinc2;
}
}
return ;
}
?>
mail AT kkapsner DOT de ¶
14 years ago
It IS posible to "delete" pixels from an image in PHP natively - the key-function is imageAlphaBlending:
<?php
$image = imageCreateTrueColor(101, 101);
imageSaveAlpha($image, true);
# draw a red cycle with alpha blending
$red = imageColorAllocateAlpha($image, 255, 0, 0, 30);
imageFilledEllipse($image, 50, 50, 100, 100, $red);
# disable alpha blending for deletion
imageAlphaBlending($image, false);
# paint with a complete opaque color
$trans = imageColorAllocateAlpha($image, 0, 0, 0, 127);
# you can clear every shape you like
imageFilledRectangle($image, 30, 30, 70, 70, $trans);
# enable alpha blending again
imageAlphaBlending($image, true);
# draw a green rectangle with alpha blending
$green = imageColorAllocateAlpha($image, 0, 255, 0, 40);
imageFilledRectangle($image, 40, 20, 90, 80, $green);
header("Content-Type: image/png");
imagePNG($image);
?>
bpgordon at gmail dot com ¶
19 years ago
This code converts a block of text to an image so that each character in the block defines one pixel in the image and each line in the block (delimited by \n's) builds one whole row of pixels in the image.
Usage: Place a 0 to create a white pixel. Place a 1 to create a black pixel.
Example: Entering the following digits (including the line breaks) will create a 3x3 square with a 1-pixel white border.
00000
01110
01110
01110
00000
<?php
if (isset($_POST["sendtxt"])) {
header("Content-type: image/png");
$splitted = explode("\n", $_POST["sendtxt"]);
foreach ($splitted as $tcurkey => $curval) $tsplitted[$tcurkey] = rtrim($curval);
$splitted = $tsplitted; //referencing isn't working for some reason...
$image = imagecreate(strlen($splitted[1]), count($splitted));
$white = imagecolorallocate($image, 0xFF, 0xFF, 0xFF); // don't delete this line
$black = imagecolorallocate($image, 0x00, 0x00, 0x00);
foreach($splitted as $curkey => $opelement) {
$subsplitten = preg_split("//", $opelement);
foreach($subsplitten as $subcurkey => $subopelement) {
if ($subopelement == "1" || $subopelement == ".") imagesetpixel($image, $subcurkey-1, $curkey, $black);
}
}
imagepng($image);
imagedestroy($image);
} else {
echo <<<end
<table width="1" border="0"><td>
<form method="post" action="#">
<textarea cols="30" rows="7" name="sendtxt"></textarea><br>
<input type="submit" value="render">
</form></td></table>
end; }
?>
gerben at gerbs dot net ¶
6 years ago
Note that you don't have to use imagecolorallocate to draw pixels. Instead, you can assign colors directly, which is much faster as well:
<?php
imagesetpixel($img, $x, $y, $r << 16 | $g << 8 | $b);
?>
cyberhorse at users dot sourceforge dot net ¶
14 years ago
Given an image $src and mask $mask, this applies the mask over the image, using different levels of transparency properly.
<?php
function image_mask(&$src, &$mask) {
imagesavealpha($src, true);
imagealphablending($src, false);
// scan image pixels
for ($x = 0; $x < imagesx($src); $x++) {
for ($y = 0; $y < imagesy($src); $y++) {
$mask_pix = imagecolorat($mask,$x,$y);
$mask_pix_color = imagecolorsforindex($mask, $mask_pix);
if ($mask_pix_color['alpha'] < 127) {
$src_pix = imagecolorat($src,$x,$y);
$src_pix_array = imagecolorsforindex($src, $src_pix);
imagesetpixel($src, $x, $y, imagecolorallocatealpha($src, $src_pix_array['red'], $src_pix_array['green'], $src_pix_array['blue'], 127 - $mask_pix_color['alpha']));
}
}
}
}
?>
If your mask is reversed, change 127 - $mask_pix_color['alpha'] with just $mask_pix_color['alpha']
aelitadelarobia at gmail dot com ¶
15 years ago
another gradient example that can do horizontal or vertical gradients
<?php
$width=$_GET['width'];
$height=$_GET['height'];
$starts=explode(",",$_GET['startcolor']);
$ends=explode(",",$_GET['endcolor']);
$rstart=$starts[0];
$gstart=$starts[1];
$bstart=$starts[2];
$rend=$ends[0];
$gend=$ends[1];
$bend=$ends[2];
$r=$rstart;
$g=$gstart;
$b=$bstart;
$bigger=imagecreatetruecolor($width,$height);
for ($y=0;$y<=265;$y++) {
if ($mode == 'horiz') { //if doing a horizontal gradient, reset to the starting color every row
$r=$rstart;
$g=$gstart;
$b=$bstart;
}
for ($x=0;$x<=464;$x++) {
imagesetpixel($bigger,$x,$y,imagecolorallocate($bigger,$r,$g,$b));
if ($mode=="horiz") {
if ($r != $rend) {
$r=$r+(($rend-$rstart)/$width);
}
if ($g != $gend) {
$g=$g+(($gend-$gstart)/$width);
}
if ($b != $bend) {
$b=$b+(($bend-$bstart)/$width);
}
}
}
if ($mode == "vert") {
if ($r != $rend) {
$r=$r+(($rend-$rstart)/$height);
}
if ($g != $gend) {
$g=$g+(($gend-$gstart)/$height);
}
if ($b != $bend) {
$b=$b+(($bend-$bstart)/$height);
}
}
}
header("Content-type: image/jpeg");
header('Content-Disposition: inline; filename="gradient.jpg"');
imagejpeg($bigger,NULL,99);
imagedestroy($bigger);
?>
Scott Evernden (doctor3d at gmail) ¶
16 years ago
Re: imagecreatefromtga() .. I just did some testing with what I think are valid Targa-24 and Targa-32 bit images, and modified the inner logic as follows:
<?php
if ($bytes_per_pixel == 2) // TARGA 16 - ARRRRRGG GGGBBBBB
{
$word = fileint($data, $pointer, 2);
$r = ($word & 0x7C00) >> 7;
$g = ($word & 0x03E0) >> 2;
$b = ($word & 0x001F) << 3;
$a = ($word & 0x8000) ? 127 : 0;
$color = imagecolorallocatealpha($image, $r, $g, $b, $a);
imagesetpixel($image, $x, $y, $color); }
else if ($bytes_per_pixel == 3) // TARGA 24 - BBBBBBBB GGGGGGGG RRRRRRRR
{
$r = fileint($data, $pointer, 1);
$b = fileint($data, $pointer+1, 1);
$g = fileint($data, $pointer+2, 1);
$color = imagecolorallocate($image, $r, $g, $b);
imagesetpixel($image, $x, $y, $color);
}
else if ($bytes_per_pixel == 4) // TARGA 32 - BBBBBBBB GGGGGGGG RRRRRRRR AAAAAAAA
{
$b = fileint($data, $pointer, 1);
$g = fileint($data, $pointer+1, 1);
$r = fileint($data, $pointer+2, 1);
$a = (255 - fileint($data, $pointer+3, 1)) >> 1;
$color = imagecolorallocatealpha($image, $r, $g, $b, $a);
imagesetpixel($image, $x, $y, $color);
}
?>
The red and blue tint issue seems to be fixed by this...
Scott Evernden (doctor3d at gmail) ¶
16 years ago
My last note doesn't do alpha properly, so make the following change to the appropriate lines:
$r = ($word & 0x7C00) >> 7;
$g = ($word & 0x03E0) >> 2;
$b = ($word & 0x001F) << 3;
$a = ($word & 0x8000) ? 127 : 0;
$color = imagecolorallocatealpha($image, $r, $g, $b, $a);
imagesetpixel($image, $x, $y, $color);
Scott Evernden (doctor3d at gmail) ¶
16 years ago
here's my version of imagecreatefromtga() that's been tested to work for targa 16 .. adapted from offering by zehao dot chang at gmail dot com
function imagecreatefromtga($filename)
{
$data = file_get_contents($filename);
// Extract header information
$string_length = fileint($data, 1, 1);
$data_type = fileint($data, 2, 1);
$width = fileint($data, 12, 2);
$height = fileint($data, 14, 2);
$bits_per_pixel = fileint($data, 16, 1);
$bytes_per_pixel = (int) $bits_per_pixel / 8;
// Currently only supporting RGB Data type
switch ($data_type) // Header information taken from http://astronomy.swin.edu.au/~pbourke/dataformats/tga/
{
case 2: // Uncompressed RGB image
break;
case 0: // No attached image data
case 1: // Uncompressed color-mapped image
case 3: // Uncompressed black and white image
case 9: // Runlength encoded color-mapped image
case 10: // Runlength encoded RGB image
case 11: // Compressed black and white image
case 32: // Compressed color-mapped data, using Huffman, Delta, and runlength encoding
case 33: // Compressed color-mapped data, using Huffman, Delta, and runlength encoding. 4-pass quadtree-type process
default:
return NULL; // No support for any of these types
}
// Compute things we need from the header information
$pointer = 18 + $string_length;
$x = 0; $y = $height - 1;
$image = imagecreatetruecolor($width, $height);
while ($pointer < strlen($data))
{
if ($bytes_per_pixel == 2) // TARGA 16 - ARRRRRGG GGGBBBBB
{
$word = fileint($data, $pointer, 2);
$r = ($word & 0x7C00) >> 10;
$g = ($word & 0x03E0) >> 5;
$b = ($word & 0x001F);
imagesetpixel($image, $x, $y, $r << 19 | $g << 11 | $b << 3);
}
else if ($bytes_per_pixel == 3) // TARGA 24 - RRRRRRRR GGGGGGGG BBBBBBBB
{
imagesetpixel($image, $x, $y, fileint($data, $pointer, 3));
}
else if ($bytes_per_pixel == 4) // TARGA 32 - AAAAAAAA RRRRRRRR GGGGGGGG BBBBBBBB
{
imagesetpixel($image, $x, $y, fileint($data, $pointer + 1, 3));
}
if (++$x == $width)
{
$y--;
$x = 0;
}
$pointer += $bytes_per_pixel;
}
return $image;
}
function fileint($data, $pos, $len)
{
return base_convert(bin2hex(strrev(substr($data, $pos, $len))), 16, 10);
}
zehao dot chang at gmail dot com ¶
18 years ago
Here's my stab at the imagecreatefromtga function. I used code from send at mail dot 2aj dot net and others below as a basis, and added support for targa 16, targa 24 and targa 32. However, I only support uncompressed RBG data type as that's the only one I need. (I removed the return_array feature since you can simply use imagesx() and imagesy() to get the image size).
Please note that I have not tested this with a targa 16 since I don't have one handy at the moment.
<?php
function imagecreatefromtga( $filename )
{
$handle = fopen( $filename, 'rb' );
$data = fread( $handle, filesize( $filename ) );
fclose( $handle );
// Extract header information
$string_length = base_convert( bin2hex( substr($data,1,1) ), 16, 10 );
$data_type = base_convert( bin2hex( substr($data,2,1) ), 16, 10 );
$width = base_convert( bin2hex( strrev( substr($data,12,2) ) ), 16, 10 );
$height = base_convert( bin2hex( strrev( substr($data,14,2) ) ), 16, 10 );
$bits_per_pixel = base_convert( bin2hex( substr($data,16,1) ), 16, 10 );
// Currenly I'm only supporting RGB Data type
switch( $data_type ) // Header information taken from http://astronomy.swin.edu.au/~pbourke/dataformats/tga/
{
case 2: // Uncompressed RGB image
break;
case 0: // No attached image data
case 1: // Uncompressed color-mapped image
case 3: // Uncompressed black and white image
case 9: // Runlength encoded color-mapped image
case 10: // Runlength encoded RGB image
case 11: // Compressed black and white image
case 32: // Compressed color-mapped data, using Huffman, Delta, and runlength encoding
case 33: // Compressed color-mapped data, using Huffman, Delta, and runlength encoding. 4-pass quadtree-type process
default:
return NULL; // No support for any of these types
}
// Compute things we need from the header information
$pointer = 18 + $string_length;
$bytes_per_pixel = (int) $bits_per_pixel/8;
$x = 0; $y = $height;
$image = imagecreatetruecolor($width, $height);
while ( $pointer < strlen($data) )
{
if( $bytes_per_pixel == 2 ) // TARGA 16 - ARRRRRGG GGGBBBBB
{
$low_byte = bin2hex( strrev( substr($data, $pointer, $bytes_per_pixel)));
$high_byte = bin2hex( strrev( substr($data, $pointer, $bytes_per_pixel)));
$r = base_convert( ($high_byte & 0x7C)>>2, 16, 10);
$g = base_convert( (($high_byte & 0x03)<<3) | (($low_byte & 0xE0)>>5), 16, 10);
$b = base_convert( $low_byte & 0x1F, 16, 10);
imagesetpixel( $image, $x, $y, $r<<16 | $g<<8 | $b);
}
else if( $bytes_per_pixel == 3 ) // TARGA 24 - RRRRRRRR GGGGGGGG BBBBBBBB
{
imagesetpixel( $image, $x, $y, base_convert( bin2hex( strrev( substr($data, $pointer, $bytes_per_pixel))), 16, 10));
}
else if( $bytes_per_pixel == 4 ) // TARGA 32 - AAAAAAAA RRRRRRRR GGGGGGGG BBBBBBBB
{
imagesetpixel( $image, $x, $y, base_convert( bin2hex( strrev( substr($data, $pointer, $bytes_per_pixel-1))), 16, 10));
}
if(++$x == $width)
{
$y--;
$x=0;
}
$pointer += $bytes_per_pixel;
}
return $image;
}
?>
T. Dekker ¶
19 years ago
In reply to weitheism at gmail.com:
You should probably have used ImageAlphaBlending($image, false); in your early attempts. This way any paint/fill operation replaces the alpha value of the destination.
chris at drunkenpirates dot co dot uk ¶
21 years ago
<?php
/*
An example combining the use of ImageColorAllocate, Imagesetpixel, Imagecopyresized and some basic Trig
By chris@drunkenpirates.co.uk
*/
Header("Content-type: image/png");
$height = 128;
$width = 128;
$imA = ImageCreate($width, $height);
$imB = ImageCreate($width*4, $height*4);
$bckA = ImageColorAllocate($imA, 0,0,0);
$bckB = ImageColorAllocate($imB, 0,0,0);
//GENERATE GRAY SCALE PALLETE
for($c=0;$c<256;$c++){
ImageColorAllocate($imA, $c, $c, $c);
}
//PRODUCE DATA
$m=rand(0,10);
for($c=0;$c<128;$c++){
$s= (sin( deg2rad($c*360*$m/128) )+1)*127;
$col_arr[$c]=$s;
}
for($y=0;$y<$height;$y++){
for($x=0;$x<$width;$x++){
$imgA[$x][$y]=$col_arr[$x];
}
}
for($y=0;$y<$height;$y++){
for($x=0;$x<$width;$x++){
$imgB[$x][$y]=$col_arr[$y];
}
}
//SET PIXELS
for($y=0;$y<$height;$y++){
for($x=0;$x<$width;$x++){
$imgC[$x][$y]=$imgA[$x][$y]+$imgB[$x][$y];
$s=$imgC[$x][$y]/2;
Imagesetpixel($imA,$x,$y,$s);
}
}
//RESIZE IMAGE FOR DISPLAY
Imagecopyresized ($imB, $imA, 0, 0, 0, 0, $width*4, $height*4, $width, $width);
ImagePNG($imB);
?>
dino at nordmark dot dk ¶
22 years ago
The example above diden't work, because of some errors.
This should work and it's also faster because there is only one 512*512 loop. (but it is still very slow)
<?
$filename="lena.raw";
$width=512;
$height=512;
$fp=fopen($filename, "r");
$contents=fread($fp,filesize($filename));
fclose($fp);
$image=imagecreate($width,$height);
// create greyscale palette because the image is limited to 256 colors
for ($i=0;$i<256;$i++){ ImageColorAllocate($image,$i,$i,$i);}
// This is slow, but probably the only way
for ($i=0;$i<512;$i++){
for ($j=0;$j<512;$j++){
imagesetpixel ($image,$i,$j,ord($contents[$i+$j*512]));
}
}
imagepng($image,"result.png");
imagedestroy($image);
echo "<img src=result.png></img>";
?>
--
Dino Patti
caffinated ¶
15 years ago
Want to have some fun with this function? How about edge detection! (ported from http://bitecode.co.uk/2008/07/edge-detection-in-python/)
<?php
function edge($input, $output)
{
$in_im = imageCreateFromJpeg($input);
$gx = array(array(-1, 0, 1), array(-2, 0, 2), array(-1, 0, 1));
$gy = array(array(-1, -2, -1), array(0, 0, 0), array(1, 2, 1));
$x = imagesx($in_im);
$y = imagesy($in_im);
$out_im = imagecreatetruecolor($x, $y);
$colors = array(255 => imagecolorallocate($out_im, 255, 255, 255));
for ($row = 1; $row < $x; $row++)
{
for ($col = 1; $col < $y; $col++)
{
$eyedropper =imagecolorat($in_im, $x, $y);
$color =imagecolorsforindex($in_im, $eyedropper);
$pxval = ($color['red'] + $color['green'] + $color['blue']) / 3;
$pixel_gx = $pixel_gy = 0;
for ($i = -1; $i < 2; $i++)
{
for ($j = -1; $j < 2; $j++)
{
$eyedropper =imagecolorat($in_im, $row+$i, $col+$j);
$color =imagecolorsforindex($in_im, $eyedropper);
$val = ($color['red'] + $color['green'] + $color['blue']) / 3;
$pixel_gx += $gx[$i+1][$j+1] * $val;
$pixel_gy += $gy[$i+1][$j+1] * $val;
}
}
$pixel = sqrt($pixel_gx * $pixel_gx + $pixel_gy * $pixel_gy);
$pixel = abs(255 - (int)$pixel);
if (!isset($colors[$pixel])) $colors[$pixel] = imagecolorallocate($out_im, $pixel, $pixel, $pixel);
imageSetPixel($out_im, $row, $col, $colors[$pixel]);
}
}
imagejpeg($out_im,$output, 75);
}
edge('input.jpg', 'output.jpg');
?>
CPHaxer ¶
15 years ago
Sorry for the long intro of my function, but i just want to tell how it works and - how silly sometimes the ideas are to make such functions. Have fun ;D
<?php
//@FunctionName: drawPlot
//@Parameters: drawPlot(img &$image, int $red, int $green, int $blue, int $x, int $y)
//
// img $image
// The Image it will draw on. The Image will be modified; there is no return value.
//
// int $red, int $green, int $blue
// The Colorvalues to draw with
//
// int $x, int $y
// The Location to draw the Plot.
// And this is the Mainpart, because $x and $y
// NEED NOT be rounded!
// If you want to make a Plot at [253.643891, 482];
// It will draw the Plot there. Exact at the Coordinates.
// You could use this to make smooth lines.
// They have rational Coordinates, too.
//
//@Author: Alexander Rath (*Feb 9th, 1996 ; 13 Years old)
//
//@Idea: We have in Math Geometrie now. And as the only Computerfreak
// In the class, i asked me: "How would it be, to mirror something
// At a NOT FLAT LINE."
// So I started thinking about it. First i tought about degresses - Nah!
// Then i saw:
// A point to mirror, has the SHORTEST way to the Line;
// so i just needed to make the result smooth.
// Unlike the other ways to draw pixels.
// ~I started developing this:
// PS: Sorry for bad english ( I am german )
//Lets create a TrueColor Image Resource
$image = imagecreatetruecolor(640, 480);
//Lets make it Alpha
imagealphablending($image, true);
imagesavealpha($image, true);
//...with White Background to draw on.
imagefilledrectangle($image, 0, 0, 640, 480, imagecolorallocate($image, 255, 255, 255));
//This is my little "Example"-Script
for($x = 0; $x <= 640; $x = $x + 0.01) {
$y = $x / (tan($x) + 1);
drawPlot($image, 0, 0, 0, $x, $y);
}
header("Content-type: image/png");
imagepng($image);
function drawPlot(&$func_image, $func_red, $func_green, $func_blue, $func_x, $func_y) {
$func_Right = $func_x - floor($func_x);
$func_Left = 1 - $func_Right;
$func_Bottom = $func_y - floor($func_y);
$func_Top = 1 - $func_Bottom;
$func_RightAlpha = $func_Right * 127;
$func_LeftAlpha = $func_Left * 127;
$func_LeftTop = $func_LeftAlpha * $func_Top;
$func_RightTop = $func_RightAlpha * $func_Top;
$func_LeftBottom = $func_LeftAlpha * $func_Bottom;
$func_RightBottom = $func_RightAlpha * $func_Bottom;
$func_x = floor($func_x);
$func_y = floor($func_y);
imagesetpixel($func_image, $func_x, $func_y, imagecolorallocatealpha($func_image, $func_red, $func_green, $func_blue, 127 - $func_LeftTop));
imagesetpixel($func_image, $func_x + 1, $func_y, imagecolorallocatealpha($func_image, $func_red, $func_green, $func_blue, 127 - $func_RightTop));
imagesetpixel($func_image, $func_x + 1, $func_y + 1, imagecolorallocatealpha($func_image, $func_red, $func_green, $func_blue, 127 - $func_RightBottom));
imagesetpixel($func_image, $func_x, $func_y + 1, imagecolorallocatealpha($func_image, $func_red, $func_green, $func_blue, 127 - $func_LeftBottom));
}
?>
Have fun ;D