imagedestroy
In example #1 above, the variable $bg is set but not used. Set the background to anything but black ,and it won't take effect. The example needs
imagefill($image, 0, 0, $bg);
Some other image function examples have the same issue.
imageellipse
(PHP 4 >= 4.0.6, PHP 5)
imageellipse — 画一个椭圆
说明
bool imageellipse
( resource
$image
, int $cx
, int $cy
, int $w
, int $h
, int $color
)
imageellipse() 在 image
所代表的图像中画一个中心为
cx，cy（图像左上角为
0, 0）的椭圆。w 和 h
分别指定了椭圆的宽度和高度，椭圆的颜色由 color 指定。
Note:
本函数需要 GD 2.0.2 或更高版本。
Example #1 imageellipse() 例子
<?php
// 新建一个空白图像
$image = imagecreatetruecolor(400, 300);
// 填充背景色
$bg = imagecolorallocate($image, 0, 0, 0);
// 选择椭圆的颜色
$col_ellipse = imagecolorallocate($image, 255, 255, 255);
// 画一个椭圆
imageellipse($image, 200, 150, 300, 200, $col_ellipse);
// 输出图像
header("Content-type: image/png");
imagepng($image);
?>
参数
-
image -
由图象创建函数(例如imagecreatetruecolor())返回的图象资源。
-
cx -
x-coordinate of the center.
-
cy -
y-coordinate of the center.
-
width -
The ellipse width.
-
height -
The ellipse height.
-
color -
The color of the ellipse. A color identifier created with imagecolorallocate().
返回值
成功时返回 TRUE， 或者在失败时返回 FALSE.
范例
Example #2 imageellipse() example
<?php
// Create a blank image.
$image = imagecreatetruecolor(400, 300);
// Select the background color.
$bg = imagecolorallocate($image, 0, 0, 0);
// Fill the background with the color selected above.
imagefill($image, 0, 0, $bg);
// Choose a color for the ellipse.
$col_ellipse = imagecolorallocate($image, 255, 255, 255);
// Draw the ellipse.
imageellipse($image, 200, 150, 300, 200, $col_ellipse);
// Output the image.
header("Content-type: image/png");
imagepng($image);
?>
以上例程的输出类似于：
注释
Note:
This function requires GD 2.0.2 or later.
add a note
User Contributed Notes
imageellipse
themountainlion at gmail dot com
13-Jul-2008 09:28
simon_nuttall at hotmail dot com
07-Jun-2006 01:36
This is an optimised and bug fixed version of nojer at yahoo dot com's rotatedellipse function. I've changed it so that the arguments are compatible with imageellipse. See notes on imagearc for original version.
<?php
function rotatedellipse($im, $cx, $cy, $width, $height, $rotateangle, $colour, $filled=false) {
// modified here from nojer's version
// Rotates from the three o-clock position clockwise with increasing angle.
// Arguments are compatible with imageellipse.
$width=$width/2;
$height=$height/2;
// This affects how coarse the ellipse is drawn.
$step=3;
$cosangle=cos(deg2rad($rotateangle));
$sinangle=sin(deg2rad($rotateangle));
// $px and $py are initialised to values corresponding to $angle=0.
$px=$width * $cosangle;
$py=$width * $sinangle;
for ($angle=$step; $angle<=(180+$step); $angle+=$step) {
$ox = $width * cos(deg2rad($angle));
$oy = $height * sin(deg2rad($angle));
$x = ($ox * $cosangle) - ($oy * $sinangle);
$y = ($ox * $sinangle) + ($oy * $cosangle);
if ($filled) {
triangle($im, $cx, $cy, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
triangle($im, $cx, $cy, $cx-$px, $cy-$py, $cx-$x, $cy-$y, $colour);
} else {
imageline($im, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
imageline($im, $cx-$px, $cy-$py, $cx-$x, $cy-$y, $colour);
}
$px=$x;
$py=$y;
}
}
function triangle($im, $x1,$y1, $x2,$y2, $x3,$y3, $colour) {
$coords = array($x1,$y1, $x2,$y2, $x3,$y3);
imagefilledpolygon($im, $coords, 3, $colour);
}
?>
julian
16-Jan-2005 06:23
if you want to display an ellipse in the upper left corner of an image, you can easily calculate the corresponding cx and cy values. this example will draw an ellipse having the same width and height as the image.
<?php
$ellipse_width = 100;
$ellipse_height = 200;
$ellipse_cx = ($ellipse_width / 2);
$ellipse_cy = ($ellipse_height / 2);
$img_x = $ellipse_width;
$img_y = $ellipse_height;
$img = imagecreate($img_x, $img_y);
$bg = imagecolorallocate($img, 255,255,255);
$ellipse_color = imagecolorallocate($img, 0, 0, 0);
imageellipse($img, $ellipse_cx, $ellipse_cy, $ellipse_width, $ellipse_height, $ellipse_color);
header("Content-type: image/png");
imagepng($img);
imagedestroy($img);
?>
agentyoungsoo at hanmail dot net
04-Dec-2002 08:56
When you wana use "ImageEllipse" function
in under GD 2.0.2 version, you can use "ImageArc" like bellow
----------------------------------------------------
$file_name = "test.png";
$screen_x = 300;
$screen_y = 200;
$x1 = $screen_x / 2;
$y1 = $screen_y / 2;
$radius = 30;
$image = ImageCreate($screen_x, $screen_y);
$black = ImageColorAllocate($image, 0,0,0);
ImageArc($image, $x1, $y1, $radius , $radius , 0, 360, $black);
ImagePng($image, $file_name);
ImageDestroy($image);
----------------------------------------------------