PHP Conference Japan 2024

    GD 與圖像函數

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    使用者貢獻的註釋 8 則註釋

    6
    chuckstudios at gmail dot com
    16 年前
    我寫了一個簡單的函式，將影像資源轉換為 PGM（可攜式灰階圖），以便將其饋送到 OCR 程式。它的運作方式與其他影像輸出函式相同，並且會為您轉換為灰階。

    <?php
    function imagepgm($image, $filename = null)
    {
    $pgm = "P5 ".imagesx($image)." ".imagesy($image)." 255\n";
    for(    $y = 0; $y < imagesy($image); $y++)
    {
    for(    $x = 0; $x < imagesx($image); $x++)
    {
    $colors = imagecolorsforindex($image, imagecolorat($image, $x, $y));
    $pgm .= chr(0.3 * $colors["red"] + 0.59 * $colors["green"] + 0.11 * $colors["blue"]);
    }
    }
    if(    $filename != null)
    {
    $fp = fopen($filename, "w");
    fwrite($fp, $pgm);
    fclose($fp);
    }
    else
    {
    return     $pgm;
    }
    }
    ?>
    5
    michal-ok at o2 dot pl
    19 年前
    下方提供的影像銳化函式（作者：Alex R. Austin）似乎非常耗費資源，我在兩台不同的伺服器上都無法讓它正常運作 - 嘗試銳化一張 413 x 413 的圖片時，最後出現了「致命錯誤：允許的記憶體大小 8388608 位元組已耗盡」或「內部伺服器錯誤」，或者腳本無預警終止。由於我沒有在這些伺服器上更改預設記憶體限制的權限，所以我開始尋找其他銳化函式。我找到了可在處理過的兩台伺服器上完美運作的 PHP Unsharp Mask 函式。它可以在 http://vikjavev.no/hovudsida/umtestside.php 找到。
    4
    felipensp at gmail dot com
    18 年前
    用於 GD 函式庫函式的十六進位色彩的十進位表示法。

    <?php

    // 十六進位表示法
    $var = '#FFFFFF';

    function     getRgbFromGd($color_hex) {

    return     array_map('hexdec', explode('|', wordwrap(substr($color_hex, 1), 2, '|', 1)));

    }

    print_r(getRgbFromGd($var));

    // 輸出：Array ( [0] => 255 [1] => 255 [2] => 255 )

    ?>
    -1
    shd at earthling dot net
    18 年前
    如果您需要輸出 Windows BMP 檔案的方法（例如，使用 PEAR ExcelWriter 時），可以隨意使用以下程式碼

    <?php
    function imagebmp ($im, $fn = false)
    {
    if (!    $im) return false;

    if (    $fn === false) $fn = 'php://output';
    $f = fopen ($fn, "w");
    if (!    $f) return false;

    //Image dimensions
    $biWidth = imagesx ($im);
    $biHeight = imagesy ($im);
    $biBPLine = $biWidth * 3;
    $biStride = ($biBPLine + 3) & ~3;
    $biSizeImage = $biStride * $biHeight;
    $bfOffBits = 54;
    $bfSize = $bfOffBits + $biSizeImage;

    //BITMAPFILEHEADER
    fwrite ($f, 'BM', 2);
    fwrite ($f, pack ('VvvV', $bfSize, 0, 0, $bfOffBits));

    //BITMAPINFO (BITMAPINFOHEADER)
    fwrite ($f, pack ('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));

    $numpad = $biStride - $biBPLine;
    for (    $y = $biHeight - 1; $y >= 0; --$y)
    {
    for (    $x = 0; $x < $biWidth; ++$x)
    {
    $col = imagecolorat ($im, $x, $y);
    fwrite ($f, pack ('V', $col), 3);
    }
    for (    $i = 0; $i < $numpad; ++$i)
    fwrite ($f, pack ('C', 0));
    }
    fclose ($f);
    return     true;
    }
    ?>

    它的運作方式與一般的 imagejpeg/imagepng 相同，並且只支援 GD2.0 真彩色點陣圖（這是 ExcelWriter 所要求的）。
    -2
    ingo at jache dot de
    13 年前
    我知道這對其他人來說可能看起來有點多餘，但我曾經遇到一種情況，我需要對圖像進行*強*模糊處理，但沒有安裝 ImageMagick。在同一張圖像上多次執行捲積濾波器速度非常慢，而且仍然無法獲得良好的模糊效果。

    以下函式接受一個真彩色圖像和一個介於 0.0 到 1.0 之間的模糊因子。注意：它仍然相當慢。

    <?php

    function blurImage($srcimg,$blur)
    {
    $blur = $blur*$blur;
    $blur = max(0,min(1,$blur));

    $srcw = imagesx($srcimg);
    $srch = imagesy($srcimg);

    $dstimg = imagecreatetruecolor($srcw,$srch);

    $f1a = $blur;
    $f1b = 1.0 - $blur;


    $cr = 0; $cg = 0; $cb = 0;
    $nr = 0; $ng = 0; $nb = 0;

    $rgb = imagecolorat($srcimg,0,0);
    $or = ($rgb >> 16) & 0xFF;
    $og = ($rgb >> 8) & 0xFF;
    $ob = ($rgb) & 0xFF;

    //-------------------------------------------------
    // first line is a special case
    //-------------------------------------------------
    $x = $srcw;
    $y = $srch-1;
    while (    $x--)
    {
    //horizontal blurren
    $rgb = imagecolorat($srcimg,$x,$y);
    $cr = ($rgb >> 16) & 0xFF;
    $cg = ($rgb >> 8) & 0xFF;
    $cb = ($rgb) & 0xFF;

    $nr = ($cr * $f1a) + ($or * $f1b);
    $ng = ($cg * $f1a) + ($og * $f1b);
    $nb = ($cb * $f1a) + ($ob * $f1b);

    $or = $nr;
    $og = $ng;
    $ob = $nb;

    imagesetpixel($dstimg,$x,$y,($nr << 16) | ($ng << 8) | ($nb));
    }
    //-------------------------------------------------

    //-------------------------------------------------
    // now process the entire picture
    //-------------------------------------------------
    $y = $srch-1;
    while (    $y--)
    {

    $rgb = imagecolorat($srcimg,0,$y);
    $or = ($rgb >> 16) & 0xFF;
    $og = ($rgb >> 8) & 0xFF;
    $ob = ($rgb) & 0xFF;

    $x = $srcw;
    while (    $x--)
    {
    //horizontal
    $rgb = imagecolorat($srcimg,$x,$y);
    $cr = ($rgb >> 16) & 0xFF;
    $cg = ($rgb >> 8) & 0xFF;
    $cb = ($rgb) & 0xFF;

    $nr = ($cr * $f1a) + ($or * $f1b);
    $ng = ($cg * $f1a) + ($og * $f1b);
    $nb = ($cb * $f1a) + ($ob * $f1b);

    $or = $nr;
    $og = $ng;
    $ob = $nb;


    //vertical
    $rgb = imagecolorat($dstimg,$x,$y+1);
    $vr = ($rgb >> 16) & 0xFF;
    $vg = ($rgb >> 8) & 0xFF;
    $vb = ($rgb) & 0xFF;

    $nr = ($nr * $f1a) + ($vr * $f1b);
    $ng = ($ng * $f1a) + ($vg * $f1b);
    $nb = ($nb * $f1a) + ($vb * $f1b);

    $vr = $nr;
    $vg = $ng;
    $vb = $nb;

    imagesetpixel($dstimg,$x,$y,($nr << 16) | ($ng << 8) | ($nb));
    }

    }
    //-------------------------------------------------
    return $dstimg;

    }


    $srcimg = imagecreatefromjpeg("test.jpg");
    $dstimg = blurImage($srcimg,0.2);

    header('Content-type: image/jpeg');
    echo(     imagejpeg($dstimg) );
    exit();


    ?>
    -2
    jeff at lushmedia dot com
    21 年前
    我寫了一個線上圖像函式概覽，人們可能會覺得有用。除了各種函式類別和程式碼範例的一般概覽之外，我還包含了許多函式的互動式範例，允許瀏覽者試驗參數，並即時查看結果。簡報位於紐約 PHP
    http://www.nyphp.org/content/presentations/GDintro/
    -3
    delabahan at gmail dot com
    8 年前
    這是獲取高解析度圖像的範例。

    <?php
    /**
    * Class name : resizeImage
    * Created by : wang
    * Description : This class is to resize the image from original size to new size
    */
    class resizeImage
    {
    /**
    * Function name : resize_img
    * Description : This function is to resize image
    * @param : $origimg variable is the original image
    * @param : $newimg variable is the new image
    * @param : $w variable is the width of image
    * @param : $f variable is the height of image
    */
    public function resize_img($origimg,$newimg,$w,$h){
    $info = getimagesize($origimg);
    $mime = $info['mime'];

    // Make sure that the requested file is actually an image
    if(substr($mime, 0, 6) != 'image/')
    {
    header('HTTP/1.1 400 Bad Request');
    return     'Error: requested file is not an accepted type: ' .$origimg;
    exit();
    }

    // Check they extention of image
    $extension = image_type_to_extension($info[2]);
    if(    strtolower($extension) == '.png'){
    $img = $this->resize_imagepng($origimg,$w, $h);
    imagepng($img,$newimg);
    imagedestroy($img);
    }elseif(    strtolower($extension) == '.jpeg'){
    $img = $this->resize_imagejpeg($origimg, $w, $h);
    imagejpeg($img, $newimg);
    imagedestroy($img);
    }elseif(    strtolower($extension == '.gif')){
    $img = $this->resize_imagegif($origimg, $w, $h);
    imagegif($img,$newimg);
    imagedestroy($img);
    }

    }
    /**
    * End function name : resize_img
    */

    /**
    * Function name : resize_imagepng
    * Description : This function is to resize png image
    * @param : $file variable is the original image
    * @param : $w variable is the width of image
    * @param : $f variable is the height of image
    */
    private function resize_imagepng($file, $w, $h) {
    list(    $width, $height) = getimagesize($file);
    $src = imagecreatefrompng($file);
    $dst = imagecreatetruecolor($w, $h);
    imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
    return     $dst;
    }
    /**
    * End function name : resize_imagepng
    */

    /**
    * Function name : resize_imagejpeg
    * Description : This function is to resize jpeg image
    * @param : $file variable is the original image
    * @param : $w variable is the width of image
    * @param : $f variable is the height of image
    */
    private function resize_imagejpeg($file, $w, $h) {
    list(    $width, $height) = getimagesize($file);
    $src = imagecreatefromjpeg($file);
    $dst = imagecreatetruecolor($w, $h);
    imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
    return     $dst;
    }
    /**
    * End function name : resize_imagejpeg
    */

    /**
    * Function name : resize_imagegif
    * Description : This function is to resize gif image
    * @param : $file variable is the original image
    * @param : $w variable is the width of image
    * @param : $f variable is the height of image
    */
    private function resize_imagegif($file, $w, $h) {
    list(    $width, $height) = getimagesize($file);
    $src = imagecreatefromgif($file);
    $dst = imagecreatetruecolor($w, $h);
    imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
    return     $dst;
    }
    /**
    * End function name : resize_imagegif
    */
    }
    /**
    * End class name : resizeImage
    */
    ?>
    -4
    mpyw
    8 年前
    這是黑白 imagebmp() 實作的範例。

    <?php

    /**
    * Output a black-and-white BMP image to either the browser or a file.
    *
    * @param resource $image
    * An image resource, returned by one of the image creation functions,
    * such as imagecreatetruecolor().
    *
    * @param string|null $to
    * The path or an open stream resource
    * (which is automatically being closed after this function returns)
    * to save the file to.
    * If not set or NULL, the raw image stream will be outputted directly.
    *
    * @param float $threshold
    * The number in the range of 0.0 to 1.0.
    * Brighter for larger, or darker for smaller.
    *
    * @return bool Returns TRUE on success or FALSE on failure.
    *
    */
    function imagebwbmp($image, $to = null, $threshold = 0.5)
    {
    if (    func_num_args() < 1) {
    $fmt = "imagebwbmp() expects a least 1 parameters, %d given";
    trigger_error(sprintf($fmt, func_num_args()), E_USER_WARNING);
    return;
    }
    if (!    is_resource($image)) {
    $fmt = "imagebwbmp() expects parameter 1 to be resource, %s given";
    trigger_error(sprintf($fmt, gettype($image)), E_USER_WARNING);
    return;
    }
    if (!    is_numeric($threshold)) {
    $fmt = "imagebwbmp() expects parameter 3 to be float, %s given";
    trigger_error(sprintf($fmt, gettype($threshold)), E_USER_WARNING);
    return;
    }

    if (    get_resource_type($image) !== 'gd') {
    $msg = "imagebwbmp(): supplied resource is not a valid gd resource";
    trigger_error($msg, E_USER_WARNING);
    return     false;
    }
    switch (    true) {
    case     $to === null:
    break;
    case     is_resource($to) && get_resource_type($to) === 'stream':
    case     is_string($to) && $to = fopen($to, 'wb'):
    if (    preg_match('/[waxc+]/', stream_get_meta_data($to)['mode'])) {
    break;
    }
    default:
    $msg = "imagebwbmp(): Invalid 2nd parameter, it must a writable filename or a writable stream";
    trigger_error($msg, E_USER_WARNING);
    return     false;
    }

    if (    $to === null) {
    $to = fopen('php://output', 'wb');
    }

    $biWidth = imagesx($image);
    $biHeight = imagesy($image);
    $biSizeImage = ((int)ceil($biWidth / 32) * 32 / 8 * $biHeight);
    $bfOffBits = 54 + 4 * 2; // Use two colors (black and white)
    $bfSize = $bfOffBits + $biSizeImage;

    fwrite($to, 'BM');
    fwrite($to, pack('VvvV', $bfSize, 0, 0, $bfOffBits));
    fwrite($to, pack('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 1, 0, $biSizeImage, 0, 0, 0, 0));
    fwrite($to, "\xff\xff\xff\x00"); // white
    fwrite($to, "\x00\x00\x00\x00"); // black

    for ($y = $biHeight - 1; $y >= 0; --$y) {
    $byte = 0;
    for (    $x = 0; $x < $biWidth; ++$x) {
    $rgb = imagecolorsforindex($image, imagecolorat($image, $x, $y));
    $value = (0.299 * $rgb['red'] + 0.587 * $rgb['green'] + 0.114 * $rgb['blue']) / 0xff;
    $color = (int)($value > $threshold);
    $byte = ($byte << 1) | $color;
    if (    $x % 8 === 7) {
    fwrite($to, pack('C', $byte));
    $byte = 0;
    }
    }
    if (    $x % 8) {
    fwrite($to, pack('C', $byte << (8 - $x % 8)));
    }
    if (    $x % 32) {
    fwrite($to, str_repeat("\x00", (int)((32 - $x % 32) / 8)));
    }
    }

    return     true;
    }
    ?>
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