Napisałem funkcję do skalowania obrazków. Idea polega na tym:
-->można podać wysokość i szerokość obrazka docelowego jako liczbę lub "auto"
-->można podać jedną z opcji "fill" "crop" lub "auto"
-->podanie wymiaru jako "auto" oznacza automatyczne wskoczenie do trybu "auto" (chyab nie da sie inaczej)
-->obrazki nigdy nie są zwiększane; mogą być tylko zmniejszane
-->wolne przestrzenie wypełniane są białym tłem
-->podajemy $_MAX_WIDTH_ i $_MAX_HEIGHT_ oznaczające maksymalne wymiary (to chyba jest najtrudniejsze bo obrazek docelowy nie powinien przekraczac tych wartości)
Przy testach z opcją "fill" i "crop" działa poprawnie. Przy opcji "auto" są jeszcze małe bugi. Moze by się komuś chciało z tym pobawić i dopomóc (choć pewnie nie). Za testy też byłbym wdzięczny.
<?php
/**
* The $a_mode argumant can be "fill", "crop", "auto"[default mode];
* Parameters $a_width and $a_height can be "0" or "auto" (the "auto" mode is triggered on then);
*/
function create_resampled_image( $a_source_file, $a_destination_file, $a_width, $a_height, $a_mode="auto" )
{
$_MAX_WIDTH_ = 640;
$_MAX_HEIGHT_ = 480;
list
( $source_width, $source_height ) = getimagesize( $a_source_file ); if( !$a_width ) $a_width = "auto";
if( !$a_height ) $a_height = "auto";
if( $a_width == "auto" or $a_height == "auto" ) $a_mode = "auto";
switch( $a_mode )
{
case "fill": #no mistakes found
if( $a_width >= $_MAX_WIDTH_ and $a_height >= $_MAX_HEIGHT_ ){
$a_width = $_MAX_WIDTH_;
$a_height = $_MAX_HEIGHT_;
$dest_height = $source_height;
$dest_width = $source_width;
}elseif( $a_width >= $_MAX_WIDTH_ ){
$a_width = $_MAX_WIDTH_;
$dest_height = $source_height;
$dest_width = $source_width;
}elseif( $a_height >= $_MAX_HEIGHT_ ){
$a_height = $_MAX_HEIGHT_;
$dest_height = $source_height;
$dest_width = $source_width;
}
if( ( $a_height/$source_height ) > ( $a_width/$source_width ) )
{
$dest_width = $a_width;
$dest_height = ($dest_width/$source_width)*$source_height;
$dest_left = 0;
$dest_top = ( $a_height - $dest_height ) / 2;
}else{
$dest_width = ($a_height/$source_height)*$source_width;
$dest_height = $a_height;
$dest_left = ( $a_width - $dest_width ) / 2;
$dest_top = 0;
}
if( $dest_width > $source_width ){
$dest_width = $source_width;
$dest_left = ( $a_width - $dest_width ) / 2;
}
if( $dest_height > $source_height ){
$dest_height = $source_height;
$dest_top = ( $a_height - $dest_height ) / 2;
}
break;
case "crop": #no mistakes found
if( $a_width >= $_MAX_WIDTH_ and $a_height >= $_MAX_HEIGHT_ ){
$a_width = $_MAX_WIDTH_;
$a_height = $_MAX_HEIGHT_;
$dest_height = $source_height;
$dest_width = $source_width;
}elseif( $a_width >= $_MAX_WIDTH_ ){
$a_width = $_MAX_WIDTH_;
$dest_height = $source_height;
$dest_width = $source_width;
}elseif( $a_height >= $_MAX_HEIGHT_ ){
$a_height = $_MAX_HEIGHT_;
$dest_height = $source_height;
$dest_width = $source_width;
}
if( ( $a_height/$source_height ) > ( $a_width/$source_width ) ){
$dest_width = ($a_height/$source_height)*$source_width;
$dest_height = $a_height;
$dest_left = ( $a_width - $dest_width ) / 2;
$dest_top = 0;
}else{
$dest_width = $a_width;
$dest_height = ($a_width/$source_width)*$source_height;
$dest_left = 0;
$dest_top = ( $a_height - $dest_height ) / 2;
}
if( $dest_width > $source_width ){
$dest_width = $source_width;
$dest_left = ( $a_width - $dest_width ) / 2;
}
if( $dest_height > $source_height ){
$dest_height = $source_height;
$dest_top = ( $a_height - $dest_height ) / 2;
}
break;
case "auto": #try to change this in future
if( $a_width == "auto" and $a_height == "auto" )
{
$dest_width = $source_width;
$dest_height = $source_height;
$a_width = $dest_width;
$a_height = $dest_height;
$dest_left = 0;
$dest_top = 0;
}elseif( $a_width == "auto" ){
$dest_width = ($a_height/$source_height)*$source_width;
$dest_height = $a_height;
$dest_left = 0;
$dest_top = 0;
$a_width = $dest_width;
} else{
$dest_width = $a_width;
$dest_height = ($a_width/$source_width)*$source_
$dest_top = 0;
$a_height = $dest_height;
}
if( $a_width >= $_MAX_WIDTH_ and $a_height >= $_MAX_HEIGHT_ ){
$a_width = $_MAX_WIDTH_;
$a_height = $_MAX_HEIGHT_;
$dest_height = ($a_width/$_MAX_WIDTH_)*$_MAX_HEIGHT_;
$dest_width = ($a_height/$_MAX_HEIGHT_)*$_MAX_WIDTH_;
}elseif( $a_width >= $_MAX_WIDTH_ ){
$a_width = $_MAX_WIDTH_;
$dest_height = $source_height;
$dest_width = ($a_height/$source_height)*$source_width;
}elseif( $a_height >= $_MAX_HEIGHT_ ){
$a_height = $_MAX_HEIGHT_;
$dest_height = $_MAX_HEIGHT_;
$dest_width = ($a_height/$source_height)*$source_width;
}
$dest_left = ( $a_width - $dest_width ) / 2;
$dest_top = ( $a_height - $dest_height ) / 2;
break;
}
$mime_type = file_mime_type( $a_source_file );
$src_image = imagecreatefromjpeg( $a_source_file );
$dst_image = imagecreatetruecolor( $a_width, $a_height );
$background = ImageColorAllocate( $dst_image, 255, 255, 255 );
ImageFill( $dst_image, 0, 0, $background
imagecopyresampled( $dst_image, $src_image, $dest_left, $dest_top, 0, 0, $dest_width, $dest_height, $source_width, $source_height );
imagejpeg( $dst_image, $a_destination_file
imagedestroy( $dst_image );
imagedestroy( $src_image );
}
?>
i jeszcze funkcja mime type:
<?php
function file_mime_type( $a_file )
{
if( function_exists(finfo_open) )
{
$handle = finfo_open( FILEINFO_MIME );
$mime_type = finfo_file( $handle, $a_file );
finfo_close( $handle );
return $mime_type;
}
else if( function_exists(mime_content_type) )
{
return mime_content_type($a_file);
}else{
die( _SYSTEM_NO_MIME_READER_AVALIBLE_
); }
}
?>
skalowanie obrazków w wersji zaawansowanej
Black-Berry skalowanie obrazków w wersji zaawansowanej 24.02.2008, 14:35:34 
