如何在不影响源图像的情况下在图像上放置水印。
$SourceFile = '/uploadedimage/gallery/thumble/';
$DestinationFile = '/uploadedimage/gallery/thumble/image-watermark.jpg';
$WaterMarkText = 'Copyright appsbee.com';
watermarkImage ($SourceFile, $WaterMarkText, $DestinationFile);
function watermarkImage ($SourceFile, $WaterMarkText, $DestinationFile) {
list($width, $height) = getimagesize($SourceFile);
$image_p = imagecreatetruecolor($width, $height);
$image = imagecreatefromjpeg($SourceFile);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width, $height);
$black = imagecolorallocate($image_p, 0, 0, 0);
$font = 'arial.ttf';
$font_size = 10;
imagettftext($image_p, $font_size, 0, 10, 20, $black, $font, $WaterMarkText);
if ($DestinationFile<>'') {
imagejpeg ($image_p, $DestinationFile, 100);
} else {
header('Content-Type: image/jpeg');
imagejpeg($image_p, null, 100);
};
imagedestroy($image);
imagedestroy($image_p);
};
如果我这样做，那么存在于文件夹上的图像就会生效。
答案 0 :(得分：2)
使用此类，在放水印之前只需复制原始图像。
<?php
class Watermark{
# given two images, return a blended watermarked image
# given two images, return a blended watermarked image
function create_watermark( $main_img_obj, $watermark_img_obj, $alpha_level = 100 ) {
$alpha_level /= 100; # convert 0-100 (%) alpha to decimal
# calculate our images dimensions
$main_img_obj_w = imagesx( $main_img_obj );
$main_img_obj_h = imagesy( $main_img_obj );
$watermark_img_obj_w = imagesx( $watermark_img_obj );
$watermark_img_obj_h = imagesy( $watermark_img_obj );
# determine center position coordinates
$main_img_obj_min_x = floor( ( $main_img_obj_w / 2 ) - ( $watermark_img_obj_w / 2 ) );
$main_img_obj_max_x = ceil( ( $main_img_obj_w / 2 ) + ( $watermark_img_obj_w / 2 ) );
$main_img_obj_min_y = floor( ( $main_img_obj_h / 2 ) - ( $watermark_img_obj_h / 2 ) );
$main_img_obj_max_y = ceil( ( $main_img_obj_h / 2 ) + ( $watermark_img_obj_h / 2 ) );
# create new image to hold merged changes
$return_img = imagecreatetruecolor( $main_img_obj_w, $main_img_obj_h );
# walk through main image
for( $y = 0; $y < $main_img_obj_h; $y++ ) {
for( $x = 0; $x < $main_img_obj_w; $x++ ) {
$return_color = NULL;
# determine the correct pixel location within our watermark
$watermark_x = $x - $main_img_obj_min_x;
$watermark_y = $y - $main_img_obj_min_y;
# fetch color information for both of our images
$main_rgb = imagecolorsforindex( $main_img_obj, imagecolorat( $main_img_obj, $x, $y ) );
# if our watermark has a non-transparent value at this pixel intersection
# and we're still within the bounds of the watermark image
if ( $watermark_x >= 0 && $watermark_x < $watermark_img_obj_w &&
$watermark_y >= 0 && $watermark_y < $watermark_img_obj_h ) {
$watermark_rbg = imagecolorsforindex( $watermark_img_obj, imagecolorat( $watermark_img_obj, $watermark_x, $watermark_y ) );
# using image alpha, and user specified alpha, calculate average
$watermark_alpha = round( ( ( 127 - $watermark_rbg['alpha'] ) / 127 ), 2 );
$watermark_alpha = $watermark_alpha * $alpha_level;
# calculate the color 'average' between the two - taking into account the specified alpha level
$avg_red = $this->_get_ave_color( $main_rgb['red'], $watermark_rbg['red'], $watermark_alpha );
$avg_green = $this->_get_ave_color( $main_rgb['green'], $watermark_rbg['green'], $watermark_alpha );
$avg_blue = $this->_get_ave_color( $main_rgb['blue'], $watermark_rbg['blue'], $watermark_alpha );
# calculate a color index value using the average RGB values we've determined
$return_color = $this->_get_image_color( $return_img, $avg_red, $avg_green, $avg_blue );
# if we're not dealing with an average color here, then let's just copy over the main color
} else {
$return_color = imagecolorat( $main_img_obj, $x, $y );
} # END if watermark
# draw the appropriate color onto the return image
imagesetpixel( $return_img, $x, $y, $return_color );
} # END for each X pixel
} # END for each Y pixel
# return the resulting, watermarked image for display
return $return_img;
} # END create_watermark()
# average two colors given an alpha
function _get_ave_color( $color_a, $color_b, $alpha_level ) {
return round( ( ( $color_a * ( 1 - $alpha_level ) ) + ( $color_b * $alpha_level ) ) );
} # END _get_ave_color()
# return closest pallette-color match for RGB values
function _get_image_color($im, $r, $g, $b) {
$c=imagecolorexact($im, $r, $g, $b);
if ($c!=-1) return $c;
$c=imagecolorallocate($im, $r, $g, $b);
if ($c!=-1) return $c;
return imagecolorclosest($im, $r, $g, $b);
} # EBD _get_image_color()
} # END watermark API
?>
这是如何使用它
$watermark = new Watermark();
$actual_image = imagecreatefromjpeg("images/$image_file");
$watermark_image = imagecreatefrompng("images/water_mark.png");
//create water marked image with 66% transparency
$return_img_obj = $watermark->create_watermark( $actual_image, $watermark_image, 66 );
//now save the updated image
imagejpeg($return_img_obj,"images/$image_file1");
//clear the memory
imagedestroy($actual_image);
imagedestroy($watermark_image);
imagedestroy($return_img_obj);
答案 1 :(得分：1)
不影响源图像。
只有添加包含透明图像的HTML图层，才能在不影响实际图像的情况下执行此操作。但是，作为一种保护手段，这是无用的，因为每个拥有一点技术知识的人都可以在几秒钟内获取原始图像。
答案 2 :(得分：0)
使用GD图像库：http://php.net/manual/en/book.image.php
这样我就可以创建图像的Web水印版本并存储源图像。
除非你的意思是动态添加水印，否则我不确定你能不能轻易做到。
答案 3 :(得分：0)
如果您不想影响源图像，那么我建议将透明图像放在HTML中图像上的绝对定位div中。这意味着您不必在每个页面加载时处理图像（因为您希望保持原始图像完整），并且您不必为存储额外图像而烦恼。
答案 4 :(得分：0)
从第一眼看，如果您没有为该功能提供目标文件名，我认为此代码不会影响源文件。