.PTR File Format

Introduction

The OS/2 colour pointer is a colour mouse pointer stored as a BMP file with the type code CP. It is laid out exactly like a colour OS/2 icon: a 1-bit bitmap of AND and XOR masks that decides where the pointer is transparent, then a colour image for the rest. The file header carries the hotspot, the pixel that marks where the pointer points.

Pointer files are usually named .ptr. A file with versions for several screens is a bitmap array whose entries are CP images.

Structure

The parts are those of a colour icon: two sets of headers, each starting with CP, then the mask bits and the colour image. The hotspot is in the first file header, in the fields described on the pointer page. All numbers are little-endian.

Telling it apart

The file starts with CP (43 50). After the first DIB header and its two-entry colour table comes a second file header, also starting with CP. Apart from the type code it is identical to a colour icon. A black and white pointer starts with PT and has only one file header.

Variants

• Windows bitmap (BM) – Windows bitmaps: a header, an optional palette and rows of pixels
• OS/2 bitmap array (BA) – several OS/2 bitmaps, icons or pointers for different screens, chained in one file
• OS/2 icon (IC) – a black and white OS/2 icon: AND and XOR masks in one 1-bit bitmap
• OS/2 colour icon (CI) – a colour OS/2 icon: a 1-bit mask bitmap followed by a colour image
• OS/2 pointer (PT) – a black and white OS/2 mouse pointer, with its hotspot in the header
• OS/2 colour pointer (CP) – a colour OS/2 mouse pointer: masks, a colour image and a hotspot

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