GD and Image 函数
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imagefilltoborder

(PHP 4, PHP 5)

imagefilltoborder — 区域填充到指定颜色的边界为止

说明

bool imagefilltoborder ( resource $image , int $x , int $y , int $border , int $color )

imagefilltoborder() 从 x，y（图像左上角为 0, 0）点开始用 color 颜色执行区域填充，直到碰到颜色为 border 的边界为止。【注：边界内的所有颜色都会被填充。如果指定的边界色和该点颜色相同，则没有填充。如果图像中没有该边界色，则整幅图像都会被填充。】

GD and Image 函数
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PHP手册
PHP手册 - N: 区域填充到指定颜色的边界为止

用户评论:

php at corzoogle dot com (27-Jun-2005 08:08)

pritm (.a.t.) mail (.d.0.t.) ru, your jpg black areas aren't entirely black, look *real* closely at it! so the fill will "seep through". the solution is simple, use a lossless background image format. replace this line..

<?
$im = imagecreatefrompng ('map-back.png');
?>

try it with this version of your image..

http://corz.org/public/images/demo/map-back.png
(the colours may be slightly different, just a quick conversion in my regular image viewer)

as you can see, it works perfectly..
http://corz.org/public/images/demo/filled.jpg

;o)
(or

Henrik Nyh (24-Jun-2005 09:26)

Reply to pritm (.a.t.) mail (.d.0.t.) ru below.

I had a similar problem and solved it thus:

I had to reduce the number of colors on the image I was using. It appeared to be a black and white map, but contained about 50 shades of almost black and almost white. I reduced this to two colors only (also going from JPG to GIF) so that the borders as well as the areas to be filled each were of a consistent shade.

Additionally, it did not work when I specified border colors as black (0,0,0), even though they seem to be of this exact shade in the map file. Instead, I used ImageColorAt() to pick the border color, and now everything seems to work.

Image: http://henrik.nyh.se/dump/map/europe.gif
In action: http://henrik.nyh.se/dump/map/map.html

Source:

<?php

$map = "europe.gif";

$img = ImageCreateFromGIF($map);

// Colors
$border = ImageColorAt ($img, 416, 111);  // Get color of borders - apparently (0,0,0) won't work
$red = ImageColorAllocate($img, 255, 0, 0);
$green = ImageColorAllocate($img, 0, 255, 0);

// Fill
ImageFillToBorder($img, 440, 100, $border, $red);  // Sweden
ImageFillToBorder($img, 250, 290, $border, $green);  // Great Britain

// Output image as PNG
header("Content-type: image/png");
ImagePNG($img);
ImageDestroy($img);  // Free memoryu

?>

sbuchanan at datadiver dot net (10-May-2005 11:08)

edrad's pseudo-sphere is pretty nice, but a few tweeks really improve it.  (writing out the image header so a browser actually understands it and calling imagedestroy() so we clean up memory are nice things to do, too).  Try drawing it at twice the size and then resampling it down.  Takes more CPU, but it forces antialiasing, creating a smooth arc.  Also, render it at diameter = (width - 1) * 2.  Taking one pixel off the outside keeps it off the image edge, eliminating those ugly flat spots.  Render it on white first so you can really see the edge, then switch back to the cool grey...

Oh, and use imagecreatetruecolor instead of imagecreate if you have it available.

I agree that imageellipse is easier, though.  Actually, I generate rounded corners with drop-shadows for CSS with imagefilledarc (kind of a blend of the two)  Use imagefilledellipse if drawing the whole thing, use imagefilledarc if only drawing part of it (like a corner).  If you use the 'filled' functions you can skip imagefilltoborder altogether :P

Anyway, try this for a smoother image:

<?php

  $requested_width = 300;
  $render_width = ($requested_width * 2) - 1; // -1 to back away from edge, removing flat spot
  $center = $render_width / 2; 
  $colordivs = 255 / $center;
  $im_scratch = @imagecreate($render_width, $render_width);

  //$back_color = imagecolorallocate($im_scratch, 20, 30, 40);  // try it with white so you can really see the edge first..
  $back_color = imagecolorallocate($im_scratch, 255, 255, 255);

  imagefill($im_scratch, 0, 0, $back_color);

  for ($i = 0; $i <= $center; $i++) {
    $diametre = $render_width - 2 * $i;
    $el_color = imagecolorallocate($im_scratch, $i * $colordivs, 0, 0);
    imageellipse($im_scratch, $center, $center, $diametre, $diametre, $el_color);
    imagefilltoborder($im_scratch, $center, $center, $el_color, $el_color);
  }

  // resample down, causes antialiasing, nice smooth curve!
  $im = @imagecreatetruecolor($requested_width, $requested_width);
  imagecopyresampled($im, $im_scratch, 0, 0, 0, 0, $requested_width, $requested_width, $render_width, $render_width);

  header ("Content-type: image/png");
  imagepng($im);
  ImageDestroy($im);
  ImageDestroy($im_scratch);

?>

admin at worldlanguages dot tk (10-Sep-2004 10:54)

In the example below, for those with newer GD versions, it makes more sense to replace:

imagearc($im, $center, $center, $diametre, $diametre, 0, 360, $el_color);

with:

imageellipse($im, $center, $center, $diametre, $diametre, $el_color);

This is obviously simpler.

edrad at wanadoo dot fr (11-Jun-2003 01:02)

Very useful to build a pseudo-sphere with a color gradient...

<?php
 $width = 300;
 $center = $width / 2;
 $colordivs = 255 / $center;
 $im = @imagecreate($width, $width);
 $back_color = imagecolorallocate($im, 20, 30, 40);
 imagefill($im, 0, 0, $back_color);
 for ($i = 0; $i <= $center; $i++)
 {
     $diametre = $width - 2 * $i;
    $el_color = imagecolorallocate($im, $i * $colordivs, 0, 0);
    imagearc($im, $center, $center, $diametre, $diametre, 0, 360, $el_color);
    imagefilltoborder($im, $center, $center, $el_color, $el_color);
 }
 imagepng($im);
?>

Dark Skull Software
http://www.darkskull.net

ecofarm at mullum dot com dot au (25-Jan-2001 06:18)

Great for getting that rounded button look we see a lot of at php.net ... try this sample. (remember to change png to whatever image format your version of php supports)

<?php

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


      ///// create canvas  /////

    $im = ImageCreate (80, 25);

  //define colors.. first color declared is set as background

    $blue  = ImageColorAllocate ($im, 0, 0, 255);
    $white  = ImageColorAllocate ($im, 255, 255, 255);

      // draw semi-circle arcs at each end

    ImageArc($im, 12, 12, 23, 26, 90, 270, $white);
    ImageArc($im, 67, 12, 23, 26, 270, 90, $white);

      // fill ends outside arcs with color

    ImageFillToBorder ($im, 0, 0, $white, $white);
    ImageFillToBorder ($im, 79, 0, $white, $white);

      // create the image

    ImagePng ($im);

      // destroy the image to free memory

    ImageDestroy ($im);
?>