Last updated: Fri, 13 Nov 2009

imageantialias

(PHP 4 >= 4.3.2, PHP 5)

imageantialias — Kenar yumuşatma işlevlerini uygulatır

Açıklama

bool imageantialias ( resource $resim , bool $etkin )

Hızlı çizilen kenar yumuşatma yöntemlerini çizgiler ve içi boş çokgenler için etkin kılar. Alfa bileşenlerini desteklemez. Doğrudan harmanlama yapar. Sadece gerçek renkli resimlerle çalışır.

Çizgi kalınlığı ve tarzı desteklenmez.

Kenar yumuşatmalı çizim ilkellerinin şeffaf artalanda kullanılmasının sonuçları belirsizdir. Harmanlama yöntemi çizgi rengiyle artalan rengini harmanlar. Alfa bileşen desteğinin yokluğu nedeniyle alfa kenar yumuşatması yapılamaz.

Değiştirgeler

resim: imagecreatetruecolor() gibi bir resim oluşturma işlevinden dönen bir resim verisi.
etkin: Kenar yumuşatma uygulanıp uygulanmayacağı.

Dönen Değerler

Başarı durumunda TRUE, başarısızlık durumunda FALSE döner.

Örnekler

Örnek 1 - Kenar yumuşatmalı çizginin normal çizgiyle karşılaştırılması


<?php
// İki resim oluşturalım
$aa = imagecreatetruecolor(400, 100);
$normal = imagecreatetruecolor(200, 100);

// Resmin birinde kenar yumuşatma etkin olsun
imageantialias($aa, true);

// Renkleri ayıralım
$red = imagecolorallocate($normal, 255, 0, 0);
$red_aa = imagecolorallocate($aa, 255, 0, 0);

// Resimlere birer çizgi çizelim
imageline($normal, 0, 0, 200, 100, $red);
imageline($aa, 0, 0, 200, 100, $red_aa);

// İki resmi yanyana bir resme yerleştirelim
// Soldaki kenar yumuşatmalı olsun
imagecopymerge($aa, $normal, 200, 0, 0, 0, 200, 100, 100);

// Resmi çıktılayalım
header('Content-type: image/png');

imagepng($aa);
imagedestroy($aa);
imagedestroy($normal);
?>

Yukarıdaki örnek şuna benzer bir çıktı üretir:

Notlar

Bilginize: Bu işlev sadece, PHP, PHP paketinde bulunan GD kütüphanesi ile derlenmişse kullanılabilir.

Ayrıca Bakınız

imagecreatetruecolor() - Yeni bir gerçek renkli resim oluşturur

imagearc

imagealphablending

Last updated: Fri, 13 Nov 2009

add a note User Contributed Notes
imageantialias

dsl101
31-Jul-2009 03:48


Having tried long and hard to get a decent antialiased circle function, I finally gave in a wrote something from scratch. Its very very naive - basically examining every single pixel in the enclosing square, but as a result produces very nice antialiasing, with decent control over stroke width, antialiasing amount and tightness of antialiasing. I'm sure it could be optimised considerably, but it was fast enough for what I was doing. Hope its of some use.



<?php



function imagecircleaa($img, $cx, $cy, $r, $w, $s, $t, $color) // image, centerX, centerY, radius, stroke width, aa width, tightness, color

{

    $adj = $w + $s;

    $sCol = imagecolorallocate($img, $color['r'], $color['g'], $color['b']);

    for($x = -$r - $adj; $x <= $r + $adj; $x++)

    {

        for($y = -$r - $adj; $y <= $r + $adj; $y++)

        {

            $d = sqrt($x * $x + $y * $y); // distance from pixel to center

            $err = abs($d - $r); // absolute distance from pixel to circle edge

            if($err <= $w / 2 + $s) // within the stroke width + smoothing radius

            {

                if($err <= $w / 2) // inside the stroke width so make it solid color

                {

                    $aaCol = $sCol;

                }

                else // in the antialisaing region so make it a blended color

                {

                    $err -= $w / 2; // adjust to the aliased part

                    $err = 1 - $err / $s; // adjust to between 0 and 1

                    $err = ($err - 0.5) * $t * 2; // adjust to -$t to +$t for tightness 

                    $err = ($err / sqrt(1 + $err * $err) + 1) / 2; // sigmoid curve to smooth edges

                    $rgb = imagecolorat($img, $x + $cx, $y + $cy); // Get current background color

                    $rB = ($rgb >> 16) & 0xFF;

                    $gB = ($rgb >> 8) & 0xFF;

                    $bB = $rgb & 0xFF;

                    $rDelta = ($rB - $color['r']); // change in Red from background

                    $rComp = $rB - $rDelta * $err; // mix Red

                    $gDelta = ($gB - $color['g']); // change in Red from background

                    $gComp = $gB - $gDelta * $err; // mix Red

                    $bDelta = ($bB - $color['b']); // change in Red from background

                    $bComp = $bB - $bDelta * $err; // mix Red

                    $aaCol = imagecolorallocate($img, $rComp, $gComp, $bComp);

                }

                imagesetpixel($img, $x + $cx, $y + $cy, $aaCol);

            }

        }

    }

}



$img = imagecreatetruecolor(500,500);



$cBlack = imagecolorallocate($img, 0, 0, 0);

$cGrey = imagecolorallocate($img, 120, 120, 120);

$cWhite = imagecolorallocate($img, 255, 255, 255);



imagefill($img, 0, 0, $cWhite);

imagepolygon($img, array(0, 0,200, 0, 200, 200, 0, 200), 4, cBlack);



$aWhite = array('r'=>255, 'g'=>255, 'b'=>255);

$aBlack = array('r'=>0, 'g'=>0, 'b'=>0);

$aRed = array('r'=>200, 'g'=>0, 'b'=>0);

$aGreen = array('r'=>0, 'g'=>200, 'b'=>0);

$aBlue = array('r'=>0, 'g'=>0, 'b'=>255);



// standard ellipse function for comparison

imageellipse($img, 100, 100, 50, 50, $cBlack);



// compare different tightnesses - good values are between 2 and 8

// note overall width is stroke width + 2 * aa width (e.g. 12 pixels below)

imagecircleaa($img, 50, 50, 25, 2, 5, 2, $aBlue);

imagecircleaa($img, 50, 150, 25, 2, 5, 8, $aBlue);



// different coloured background to show blending

imagefilledrectangle($img, 150,150, 200, 200, $cGrey);

imagecircleaa($img, 150, 150, 25, 3, 2, 2, $aRed);



// overlapping circles still aa nicely, although the colour blending algorithm produces quite dark intermediate shades

imagecircleaa($img, 150, 60, 25, 2, 3, 2, $aBlue);

imagecircleaa($img, 150, 50, 25, 2, 3, 2, $aGreen);



header("Content-type: image/png");

imagepng($img);

imagedestroy($img);

?>

Ulrich M.
20-Dec-2007 04:07


An updated version of my antialiased arc script is now available at:

http://mierendo.com/software/antialiased_arcs/

Have fun with it!

Godfather of Image Processing
22-Feb-2007 06:05


Of course, this IS a way to do antialiasing. Graphiccards do so. But for good results you should use at least a 4 times bigger source image than the destination to scale down. This is a 16 times higher fillrate. If you only use the proposed doublesized image, quality is still poor...

padigan
06-Feb-2007 11:13


If you can't be bothered creating (or searching for) a full screen antialias function.

You can actually cheat (well a bit of a dirty inefficient hack really!!) 

and perform a fake antialias on an image by using 'imagecopyresampled'...



first create your source image twice the size of what you really want.



Then use 'imagecopyresampled' to shrink it to half the size, the function 

automatically interpolates pixels to create an antialias effect!



I've used this in a pie chart function and it works brilliantly,

not as slow as I thought it might be!



the rough code below should give you the idea...



<?php

$realWidth = 500;

$realHeight = 500;

$srcWidth = $realWidth * 2;

$srcHeight = $realHeight * 2;



// create the larger source image

$srcImage = imagecreatetruecolor($srcWidth,$srcHeight);



// create the real/final image

$destImage = imagecreatetruecolor($realWidth,$realHeight);



// now do whatever you want to draw in the source image

// blah....



// now the picture is finished, do the shrink...

imagecopyresampled($destImage,$srcImage,0,0,0,0,

$realWidth,$realHeight,$srcWidth,$srcHeight);



// now just do whatever you want with '$destImage' (e.g. display or output to file!)

?>

Ulrich Mierendorff
10-Aug-2006 07:39


I've written a php function which draws antialiased and filled elliptic arcs (segments of ellipses or full ellipses). It does not require the imageantialias function of php!

It's available at

http://icewind.ic.funpic.de/index.php?content=ellipse

Best Regards,

Ulrich

php at 3d-box dot com
08-Jul-2006 04:55


This might help some people but I have created an antialiased, filled, ellipse function - the source for which is here:-



http://personal.3d-box.com/php/filledellipseaa.php



As the code is too much to put here!

jb at flamedesign dot dk
30-Mar-2006 10:37


Official GD Lib manual link:



http://www.boutell.com/gd/manual2.0.33.html#gdImageSetAntiAliased

n-dream at gmx dot ch
18-Feb-2006 06:18


The following function draws an AntiAliased (unfilled) Ellipse.

It is used just liked the nomral ImageEllipse function.

The optional parameter sets the number of segments...



function ImageEllipseAA( &$img, $x, $y, $w, $h,$color,$segments=70) 

{

    $w=$w/2;

    $h=$h/2;

    $jump=2*M_PI/$segments;

    $oldx=$x+sin(-$jump)*$w;

    $oldy=$y+cos(-$jump)*$h;

    for($i=0;$i<2*(M_PI);$i+=$jump)

    {

        $newx=$x+sin($i)*$w;

        $newy=$y+cos($i)*$h;

        ImageLine($img,$newx,$newy,$oldx,$oldy,$color);

        $oldx=$newx;

        $oldy=$newy;

    }

}

klaas at kosmokrator dot com
15-Feb-2006 01:22


Here is an optimized version of the optimized version of the antialiased circle function by sebbi: (more than 20 times faster)...



<?php



    function imageSmoothCircle( &$img, $cx, $cy, $cr, $color ) {

        $ir = $cr;

        $ix = 0;

        $iy = $ir;

        $ig = 2 * $ir - 3;

        $idgr = -6;

        $idgd = 4 * $ir - 10;

        $fill = imageColorExactAlpha( $img, $color[ 'R' ], $color[ 'G' ], $color[ 'B' ], 0 );

        imageLine( $img, $cx + $cr - 1, $cy, $cx, $cy, $fill );

        imageLine( $img, $cx - $cr + 1, $cy, $cx - 1, $cy, $fill );

        imageLine( $img, $cx, $cy + $cr - 1, $cx, $cy + 1, $fill );

        imageLine( $img, $cx, $cy - $cr + 1, $cx, $cy - 1, $fill );

        $draw = imageColorExactAlpha( $img, $color[ 'R' ], $color[ 'G' ], $color[ 'B' ], 42 );

        imageSetPixel( $img, $cx + $cr, $cy, $draw );

        imageSetPixel( $img, $cx - $cr, $cy, $draw );

        imageSetPixel( $img, $cx, $cy + $cr, $draw );

        imageSetPixel( $img, $cx, $cy - $cr, $draw );

        while ( $ix <= $iy - 2 ) {

            if ( $ig < 0 ) {

                $ig += $idgd;

                $idgd -= 8;

                $iy--;

            } else {

                $ig += $idgr;

                $idgd -= 4;

            }

            $idgr -= 4;

            $ix++;

            imageLine( $img, $cx + $ix, $cy + $iy - 1, $cx + $ix, $cy + $ix, $fill );

            imageLine( $img, $cx + $ix, $cy - $iy + 1, $cx + $ix, $cy - $ix, $fill );

            imageLine( $img, $cx - $ix, $cy + $iy - 1, $cx - $ix, $cy + $ix, $fill );

            imageLine( $img, $cx - $ix, $cy - $iy + 1, $cx - $ix, $cy - $ix, $fill );

            imageLine( $img, $cx + $iy - 1, $cy + $ix, $cx + $ix, $cy + $ix, $fill );

            imageLine( $img, $cx + $iy - 1, $cy - $ix, $cx + $ix, $cy - $ix, $fill );

            imageLine( $img, $cx - $iy + 1, $cy + $ix, $cx - $ix, $cy + $ix, $fill );

            imageLine( $img, $cx - $iy + 1, $cy - $ix, $cx - $ix, $cy - $ix, $fill );

            $filled = 0;

            for ( $xx = $ix - 0.45; $xx < $ix + 0.5; $xx += 0.2 ) {

                for ( $yy = $iy - 0.45; $yy < $iy + 0.5; $yy += 0.2 ) {

                    if ( sqrt( pow( $xx, 2 ) + pow( $yy, 2 ) ) < $cr ) $filled += 4;

                }

            }

            $draw = imageColorExactAlpha( $img, $color[ 'R' ], $color[ 'G' ], $color[ 'B' ], ( 100 - $filled ) );

            imageSetPixel( $img, $cx + $ix, $cy + $iy, $draw );

            imageSetPixel( $img, $cx + $ix, $cy - $iy, $draw );

            imageSetPixel( $img, $cx - $ix, $cy + $iy, $draw );

            imageSetPixel( $img, $cx - $ix, $cy - $iy, $draw );

            imageSetPixel( $img, $cx + $iy, $cy + $ix, $draw );

            imageSetPixel( $img, $cx + $iy, $cy - $ix, $draw );

            imageSetPixel( $img, $cx - $iy, $cy + $ix, $draw );

            imageSetPixel( $img, $cx - $iy, $cy - $ix, $draw );

        }

    }



    $img = imageCreateTrueColor( 320, 240 );



    imageSmoothCircle( $img, 160, 120, 100, array( 'R' => 0xCC, 'G' => 0x33, 'B' => 0x00 ) );

    imageSmoothCircle( $img, 170, 110,  75, array( 'R' => 0xDD, 'G' => 0x66, 'B' => 0x00 ) );

    imageSmoothCircle( $img, 180, 100,  50, array( 'R' => 0xEE, 'G' => 0x99, 'B' => 0x00 ) );

    imageSmoothCircle( $img, 190,  90,  25, array( 'R' => 0xFF, 'G' => 0xCC, 'B' => 0x00 ) );



    header( 'Content-Type: image/png' );

    imagePNG( $img );



?>

voinic at NOSgmailPAM dot com
12-Jan-2006 10:22


The only trick I found to draw an antialiased polygon AND keep it transparent (to use them as overlays in google maps for example)... make two images and merge them. Order of operations is important and the transparency color of the final image must be set after the merge:



<?

header("Content-type: image/png");



$values = array(

           40,  50,  // Point 1 (x, y)

           20,  240, // Point 2 (x, y)

           60,  60,  // Point 3 (x, y)

           240, 20,  // Point 4 (x, y)

           50,  40,  // Point 5 (x, y)

           10,  10  // Point 6 (x, y)

           );                    



$im = imagecreate(250, 250);

$bg = imagecolorallocate($im, 255, 255, 255);



$im2 = imagecreatetruecolor(250, 250);

$bg2 = imagecolorallocate($im2, 255, 255, 255);

imagefilledrectangle($im2,0,0,249,249,$bg2);

imagecolortransparent($im2, $bg);

imageantialias($im2, true);

$c_red = imagecolorallocate($im2, 255, 0, 0);

imagepolygon($im2, $values, 6, $c_red);

imageantialias($im2, false);



imagecopymerge($im, $im2,0,0,0,0,250,250,50);



imagecolortransparent($im, $bg);

$c_red_alpha = imagecolorallocatealpha($im, 255, 0, 0, 60);

imagefilledpolygon($im, $values, 6, $c_red_alpha);



imagepng($im);

imagedestroy($im);

imagedestroy($im2);

?>

sebbi at conceptT dot com
26-Sep-2005 02:06


I did a search in google and got following url:

http://www.isocalc.com/tutorials/antialias.htm

With this tutorial I was able to write a function to convert this algorithm into php, the result for a filled circel is this:

<?php

function imagefilledcircleantialiased(&$im, $cx, $cy, $r, $fgcolor, $bgcolor) {

  $fgcolors = imagecolorsforindex($im,$fgcolor);

  $bgcolors = imagecolorsforindex($im,$bgcolor);

  for ( $x = $cx - $r; $x <= $cx + $r; $x++ ) {

    for ( $y = $cy - $r; $y <= $cy + $r; $y++ ) {

      $rx = $x - $cx; $ry = $y - $cy;

      $ir = sqrt(( $rx == 0 ? 0 : pow($rx - 0.5*abs($rx)/$rx, 2) ) + ( $ry == 0 ? 0 : pow($ry - 0.5*abs($ry)/$ry, 2) ));

      $or = sqrt(( $rx == 0 ? 0 : pow($rx + 0.5*abs($rx)/$rx, 2) ) + ( $ry == 0 ? 0 : pow($ry + 0.5*abs($ry)/$ry, 2) ));

      if ( $or <= $r ) {

        imagesetpixel($im, $x, $y, $fgcolor);

      }

      elseif ( $ir < $r ) {

        $filled = 0;

        for ( $xx = $x - 0.45; $xx < $x + 0.5; $xx+=0.1 ) {

          for ( $yy = $y - 0.45; $yy < $y + 0.5; $yy+=0.1 ) {

            $rxx = $xx - $cx; $ryy = $yy - $cy;

            if ( sqrt(pow($rxx, 2) + pow($ryy, 2)) < $r ) $filled++;

          }

        }

        $red = round($bgcolors['red'] + ( $fgcolors['red'] - $bgcolors['red'] ) * $filled / 100);

        $green = round($bgcolors['green'] + ( $fgcolors['green'] - $bgcolors['green'] ) * $filled / 100);

        $blue = round($bgcolors['blue'] + ( $fgcolors['blue'] - $bgcolors['blue'] ) * $filled / 100);

        imagesetpixel($im, $x, $y, imagecolorclosest($im, $red, $green, $blue));

      }

    }

  }

}



$width = 160;

$height = 200;

$r = 20;

$bgc = "651713";

$fgc = "b12b2c";



$im = imagecreate($width, $height);

$bgcolor = imagecolorallocate($im, hexdec(substr($bgc, 0, 2)), hexdec(substr($bgc, 2, 2)), hexdec(substr($bgc, 4, 2)));

for( $i = 0; $i < 100; $i++ ) {

    imagecolorallocate($im, ( hexdec(substr($fgc, 0, 2)) + $i*hexdec(substr($bgc, 0, 2))) / ($i + 1), ( hexdec(substr($fgc, 2, 2)) + $i*hexdec(substr($bgc, 2, 2))) / ($i + 1), ( hexdec(substr($fgc, 4, 2)) + $i*hexdec(substr($bgc, 4, 2))) / ($i + 1));

}

$fgcolor = imagecolorclosest($im, hexdec(substr($fgc, 0, 2)), hexdec(substr($fgc, 2, 2)), hexdec(substr($fgc, 4, 2)));



imagefilledcircleantialiased($im, 80, 100, $r, $fgcolor, $bgcolor);



header("Content-Type: image/png");

imagepng($im);

?>

An improvement would be to draw the inner rectangle or more rectangles in the circle with the builtin rectangle function to reduce the usage of imagesetpixel() from (2*r)^2 to 2*Pi*(r + epsilon), in other words, the dependency on r would break down from square to linear.

Another improvement would be to determine filled and unfilled triangles in the observed pixel and calculate their areas, so we can get rid of the inner loops for getting the fraction filled/unfilled.

One can easily modify this function to solve other problems like lines, unfilled circles, etc.

trimbo
06-Sep-2005 07:25


So far using PHP 5.0.4 I've managed to get Imageantialias() to work well with:

ImageLine()

ImagePolygon()



but not with:

ImageArc()

ImageEllipse()

ImageFilled*()



You can still draw antialiased filled polygons by drawing a hollow polygon on top of a filled one with the same dimensions:

<?php

        $points=array($x,$y, $x2,$y2, $x3,$y3);

        imageFilledPolygon($im, $points, 3, $gray );

        imagePolygon($im, $points, 3, $gray );

?>

klaas at kosmokrator dot com
24-May-2004 02:21


I have optimized the "imageSmoothLine" function by logang.



sample and download at:



http://www.kosmokrator.com/download/php/

add a note

imagearc

imagealphablending

Last updated: Fri, 13 Nov 2009