imagegd2

    (PHP 4 >= 4.0.7, PHP 5, PHP 7, PHP 8)

    imagegd2 — 将 GD2 图像输出到浏览器或文件

    说明

    imagegd2(
        GdImage $image,
        ?string $file = null,
        int $chunk_size = 128,
        int $mode = IMG_GD2_RAW
    ): bool

    输出 GD2 图像到指定 file。

    参数

    image

    由图象创建函数(例如imagecreatetruecolor())返回的 GdImage 对象。

    file

    文件保存的路径或者已打开的流资源（此方法返回后自动关闭该流资源），如果未设置或为 null，将会直接输出原始图象流。

    chunk_size

    块大小。

    mode

    可以是 IMG_GD2_RAW 或 IMG_GD2_COMPRESSED。默认为 IMG_GD2_RAW。

    返回值

    成功时返回 true， 或者在失败时返回 false。

    警告

    如果 libgd 输出图像失败，函数会返回 true。

    更新日志

    版本 说明
    8.0.3 file 现在可以为 null。
    8.0.0 image 现在需要 GdImage 实例；之前需要有效的 gd resource。

    示例

    示例 #1 输出 GD2 图像

    <?php
    // Create a blank image and add some text
    $im = imagecreatetruecolor(120, 20);
    $text_color = imagecolorallocate($im, 233, 14, 91);
    imagestring($im, 1, 5, 5, "A Simple Text String", $text_color);

    // Output the image
    imagegd2($im);

    // Free up memory
    imagedestroy($im);
    ?>

    示例 #2 保存 GD2 图像

    <?php
    // Create a blank image and add some text
    $im = imagecreatetruecolor(120, 20);
    $text_color = imagecolorallocate($im, 233, 14, 91);
    imagestring($im, 1, 5, 5, "A Simple Text String", $text_color);

    // Save the gd2 image
    // The file format for GD2 images is .gd2, see http://www.libgd.org/GdFileFormats
    imagegd2($im, 'simple.gd2');

    // Free up memory
    imagedestroy($im);
    ?>

    注释

    注意:

    GD2 格式通常用于允许快速加载部分图像。请注意，GD2 格式仅可用于与 GD2 兼容的应用程序。

    警告

    The GD and GD2 image formats are proprietary image formats of libgd. They have to be regarded obsolete, and should only be used for development and testing purposes.

    参见

    • imagegd() - 将 GD 图像输出到浏览器或文件

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    用户贡献的备注 2 notes

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    3
    Nick
    13 years ago
    You can use this function in combination with imagecreatefromstring() to clone the gd resource with minimum fuss (no writing to tmp file):

    <?php
    function cloneGd($gd)
    {
    ob_start();
    imagegd2($gd);
    return     imagecreatefromstring(ob_get_clean());
    }
    ?>
    up
    0
    mark at teckis dot com
    21 years ago
    yes, the gd2 file format does improve the speed of image creations as the data-setup is designed to be native for the GD function - ie, the image doesn't have to be converted to a usable format prior to processing.

    you may also note that the newer gd2 format creates much smaller size files than the older imagegd function, certainly for images involving chunks of single colours anyway. you'll probably find this function most useful for saving overlay images or background images used in larger image creation scripts.

    to read a ping or jpeg image (.png / .jpg) and save a .gd2 version to server...

    $img = $_GET['img'];
    if(file_exists($img))
    {
    $dim = getimagesize($img);
    $cr = ($dim[2] < 4) ? ($dim[2] < 3) ? ($dim[2] < 2) ? NULL : imagecreatefromjpeg($img) : imagecreatefrompng($img) : Null;
    if($cr !== NULL)
    {
    imagegd2($cr,substr($img,0,strrpos($img,'.')).'.gd2');
    }
    }

    should save a copy with the same filename and directory using extension .gd2 - which can then be nicely and swiftly read using either imagecreatefromgd2 or imagecreatefromgd2part
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