Načtení PCX v PHP – PHP – Fórum – Programujte.com

AHoj měl bych dotaz,
jde pomocí PHP načíst formát obrázku PCX a jeho následná úprava?

Díky

To Petr : Nelze, GD knihovna zvládá pouze GIF, JPEG, GD, PNG, WBMP

To Petr : Leda, kdyby se Ti chtělo experimentovat, tak můžeš zkusit: http://pear.php.net/package/Image_Transform/docs/latest/li_Image_Transform.html - údajně to podporuje i PCX... Ale na tohle by si už musel být zběhlejší v PHP.

mozna imagick... pripadne nejaky externi program na koncerzi a pak prace s image v php pomoci toho gd/imagick

You stille can process the 256-color PCX image file format manually in PHP, because it is an extremely simple format - we used to learn C++ on this! I still remember the basics.

Here is how You extract HEADER in PHP:

link  stackoverflow.com/questions/9362954/php-convert-single-byte-to-integer-pcx-graphic-format

And from the Wiki, you know that if the picture is the most common 256-color PCX with palette, than processing the data is extremely simple:

1. Palette: last 768 bytes of the file in plain simple format: 3 bytes for  R G B  for colors with number 0 to 255 , like this: first triplet of bytes are RGB values for color zero, second for color 1  etc... , at positions simply as we read it.. in the order RGB : byte number 3*colour_num (Red) , byte num. 3*colour_num + 1 (Green)  , byte num. 3*color_num+2 (Blue).

2. Data :)  ... in order, as we read it from left to right, simply, there are only TWO possibilities:

a) IF the byte is from 0 to 191 included - it means single pixel of this colour - hence 0 to 191... the byte value IS the colour.

b) ELSE: the byte has value 192 to 255 - means: the NEXT byte is the colour of a pixel (on this line, in normal order, hence left-to-right...),  which repeats itself (the same colour)  THIS MANY TIMES:  byteValue - 192   ;  for example, byte pair of:  194 255  means:(194 - 192) = 2 times repeats pixel of COLOUR number 255

That's all.  Actually really easy to implement in PHP (or in any language). :)  .... the pallette-conversion-PHP-code into RGB truecolor image for the GD library will be also this simple! You have all those values here in the pallette at the end [last 768 bytes] of the PCX!   Just use them to set R G B bytes of truecolor pixel in the image :)))