Online Photo Album Development using PHP and GD: Part 1 - Resizing Images
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Again, we make use of GD's imagecreatetruecolor() to create a pointer to a true-colored image.
imagecopyresampled($tmp_resize, $this->img, 0, 0, 0, 0, RESIZE_WIDTH, RESIZE_HEIGHT, $this->width, $this->height);
imagedestroy($this->img);
$this->resize = $tmp_resize;
We then resize our image to the specified size, passing to it the temporary image pointer, the original image, and the 4 parameters dealing with the co-ordinates and size (similar to the ones passed in the setThumbnail() function.
GD has a built-in function to destroy the original image uploaded. We'll use this function once our image has been resized, followed by assigning the value of $tmp_resize, to our resized image object ($this->resize).
/*****
* Copies thumbnail image to specified thumbnail directory.
* Sets permissions on file
*/
function copyThumbImage(){
imagejpeg($this->thumb, $this->thumbnail);
if(!@copy($this->thumbnail, THUMB_BASE . $this->thumbnail)){
echo("Error processing file... Please try again!");
return false;
}
if(!@chmod($this->thumbnail, 666)){
echo("Error processing file... Please try again!");
return false;
}
if(!@unlink($this->thumbnail)){
echo("Error processing file... Please try again!");
return false;
}
return true;
}
Because we're not storing our images in a database, we need to copy the file over to our new images to our desired directories, specified in our constant variables.
imagejpeg($this->thumb, $this->thumbnail);
The imagejpeg() function will actually write the JPEG file information to a file that will now reside in the filesystem. We pass, as arguments, the thumbnail pointer ($this->thumb) and the object which will represent the actual thumbnail file ($this->thumbnail).
We then copy the image to our thumbnail directory, set the desired permissions (making use of PHP's chmod() function), and unlink/delete the temporary thumbnail image.
/*****
* Copies the resized image to the specified images directory.
* Sets permissions on file.
*/
function copyResizedImage(){
imagejpeg($this->resize, $this->converted);
if(!@copy($this->converted, IMAGE_BASE . $this->converted)){
echo("Error processing file... Please try again!");
return false;
}
if(!@chmod($this->converted, 666)){
echo("Error processing file... Please try again!");
return false;
}
if(!unlink($this->converted)){
echo("Error processing file... Please try again!");
return false;
}
// Delete the original uploaded image
if(!unlink(IMAGE_BASE . $this->image_file)){
echo("Error processing file... Please try again!");
return false;
}
return true;
}
Our copyResizedImage() function is identical to the copyThumbImage() function, except that we work with the resized image rather than the thumbnail.
/*****
* Generates a random number. Random number is used to rename
* the original uploaded image, once resized.
*/
function getRandom(){
return "_" . date("dmy_His");
}
Our getRandom() function simply returns a string value with the current date and time with a seconds value.
/*****
* Returns path to thumbnail image
*/
function getThumbLocation(){
return "thumbs/" . $this->random_file;
}
The getThumbLocation() function returns the path to our thumbnail image, so that the value may be inserted into our database for retrieval later on.
/*****
* Returns path to resized image
*/
function getImageLocation(){
return "photos/" . $this->random_file;
}
The getImageLocation() returns the path to our resized image, which will be inserted into our database for retrieval later on.
Next: Conclusion >>
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