使用图像滤镜功能无法正确改变图像颜色

我尝试了此方法并工作-大部分是:)我将您的棕色图像另存为img1.png。

        <?php 

    function colorizeKeepAplhaChannnel( $inputFilePathIn, $targetRedIn, $targetGreenIn, $targetBlueIn, $outputFilePathIn ) {
        $im_src = imagecreatefrompng( $inputFilePathIn );
        $im_dst = imagecreatefrompng( $inputFilePathIn );
        $width = imagesx($im_src);
        $height = imagesy($im_src);

        // Note this: FILL IMAGE WITH TRANSPARENT BG
        imagefill($im_dst, 0, 0, IMG_COLOR_TRANSPARENT);
        imagesavealpha($im_dst,true);
        imagealphablending($im_dst, true);


        $flagOK = 1;
        for( $x=0; $x<$width; $x++ ) {
            for( $y=0; $y<$height; $y++ ) {
                $rgb = imagecolorat( $im_src, $x, $y );

                $colorOldRGB = imagecolorsforindex($im_src, $rgb);
                $alpha = $colorOldRGB["alpha"];

               //echo "$colorOldRGB[red], $colorOldRGB[green],$colorOldRGB[blue] <br/>\n";

                if($colorOldRGB["red"] >150 && $colorOldRGB["green"] >150 && $colorOldRGB["blue"] >150) {
                    $newRed = $colorOldRGB["red"];
                    $newGreen = $colorOldRGB["green"];
                    $newBlue = $colorOldRGB["blue"];

                }
                else if($colorOldRGB["red"] === 0 && $colorOldRGB["green"] === 0 && $colorOldRGB["blue"] === 0) {
                    $newRed = 0;
                    $newGreen = 0;
                    $newBlue = 0;         
                }
                else {
//                    $newRed = 0 - $colorOldRGB["red"] + $targetRedIn;
//                    $newGreen =0 - $colorOldRGB["green"] + $targetGreenIn;
//                    $newBlue = 0 - $colorOldRGB["blue"] + $targetBlueIn; 


                    $newRed = $targetRedIn;
                    $newGreen =  $targetGreenIn;
                    $newBlue =  $targetBlueIn; 

                }


                if($newRed <0 ) {
                    $newRed = 0;
                }
                if($newRed >255) {
                    $newRed = 255;
                }

                if($newGreen <0){
                    $newGreen = 0;
                }
                if($newGreen>255) {
                    $newGreen = 255;
                }

                if($newBlue<0) {
                    $newBlue = 0;
                }
                if($newBlue>255) {
                    $newBlue = 255;
                }




                //$colorNew = imagecolorallocatealpha($im_src, $targetRedIn, $targetGreenIn, $targetBlueIn, $alpha);
                $colorNew = imagecolorallocatealpha($im_src, $newRed, $newGreen, $newBlue, $alpha);

                $flagFoundColor = true;
                // uncomment next 3 lines to substitute only 1 color (in this case, BLACK/greys)
    /*
                $colorOld = imagecolorallocatealpha($im_src, $colorOldRGB["red"], $colorOldRGB["green"], $colorOldRGB["blue"], 0); // original color WITHOUT alpha channel
                $color2Change = imagecolorallocatealpha($im_src, 0, 0, 0, 0); // opaque BLACK - change to desired color
                $flagFoundColor = ($color2Change == $colorOld);
    */

                if ( false === $colorNew ) {
                    //echo( "FALSE COLOR:$colorNew alpha:$alpha<br/>" );
                    $flagOK = 0; 
                } else if ($flagFoundColor) {
                    imagesetpixel( $im_dst, $x, $y, $colorNew );
                    //echo "x:$x y:$y col=$colorNew alpha:$alpha<br/>";
                } 
            }
        }
        $flagOK2 = imagepng($im_dst, $outputFilePathIn);

        if ($flagOK && $flagOK2) {
            echo ("<strong>Congratulations, your conversion was successful </strong><br/>new file $outputFilePathIn<br/>");
        } else if ($flagOK2 && !$flagOK) {
            echo ("<strong>ERROR, your conversion was UNsuccessful</strong><br/>Please verify if your PNG is truecolor<br/>input file $inputFilePathIn<br/>");
        } else if (!$flagOK2 && $flagOK) {
            $dirNameOutput = dirname($outputFilePathIn)."/";
            echo ("<strong>ERROR, your conversion was successful, but could not save file</strong><br/>Please verify that you have PERMISSION to save to directory $dirName <br/>input file $inputFilePathIn<br/>");
        } else {
            $dirNameOutput = dirname($outputFilePathIn)."/";
            echo ("<strong>ERROR, your conversion was UNsuccessful AND could not save file</strong><br/>Please verify if your PNG is truecolor<br/>Please verify that you have PERMISSION to save to directory $dirName <br/>input file $inputFilePathIn<br/>");
        }

        echo ("TargetName:$outputFilePathIn wid:$width height:$height CONVERTED:|$flagOK| SAVED:|$flagOK2|<br/>");
        imagedestroy($im_dst);
        imagedestroy($im_src);
    }

    $targetRed = 0;
    $targetGreen = 128;
    $targetBlue = 64;

    //$inputFileName = 'frameSquareBlack_88x110.png';
    $inputFileName = 'img1.png';
    $dirName = "./images/";
    $nameTemp = basename($inputFileName, ".png");
    $outputFileName = $nameTemp."_$targetRed"."_$targetGreen"."_$targetBlue.png";
    $inputFilePath = $dirName.$inputFileName;
    $outputFilePath = $dirName.$outputFileName;

    //echo "inputFileName:$inputFilePath<br>outputName:$outputFilePath<br>";
    colorizeKeepAplhaChannnel( $inputFilePath, $targetRed, $targetGreen, $targetBlue, $outputFilePath);
    ?>
    <br/><br/>
    Original <br/>
    <img src="<?php echo $inputFilePath; ?>">
    <br /><br />Colorized<br/>
    <img src="<?php echo $outputFilePath; ?>">
    <br />