MMA_Video_BitsPerPixel

MMA_Video_BitsPerPixel (V50) [..G.Q], ULONG

DESCRIPTION

   Returns image colour depth. Possible values for png.decoder are 1, 2,
   3, 4, 5, 6, 7, 8, 24, 32

MMA_Video_Height

MMA_Video_Height (V50) [..G.Q], ULONG

DESCRIPTION

   Returns height of image frame in pixels

MMA_Video_UseAlpha

MMA_Video_UseAlpha (V50) [..G.Q], BOOL

DESCRIPTION

   Returns TRUE if PNG image data contain alpha channel, FALSE
   otherwise

MMA_Video_Width

MMA_Video_Width (V50) [..G.Q], ULONG

DESCRIPTION

   Returns width of image frame in pixels

MMM_Pull

Writes encoded data to specified buffer. (V50)

SYNOPSIS

   ULONG DoMethod(Object *obj, MMM_Pull, ULONG port, APTR buffer, ULONG
     length);

DESCRIPTION

   This class does not process image data,  pull requests are
   just forwarded to the connected stream

INPUTS

   obj - object to perform method on.
   port - number of port, must be output (1).
   buffer - destination buffer for bitmap data.
   length - amount of data to be pulled in bytes

RESULT

   Number of bytes pulled, secondary error information via MMA_ErrorCode

SEE ALSO

background

HISTORY

   51.6 (24.12.2021)
   - Added support for interlaced images

   51.5 (19.12.2017)
   - Fixed support for palette images with color key

   51.4 (15.05.2017)
   - Handle incomplete read properly (call png_error)
   - Have more consistent error handling
   - Implement missing MMM_Cleanup
   - setjmp the error handler in each function calling
     png_ functions

   51.3 (24.10.2015)
   - Fix for per-output metadata.

   51.2 (09.04.2013)
   - Use of png.library
   - MMETA_VideoDpiX, MMETA_VideoDpiY tag support
   - Optimizations
   - Support of gray images with alpha channel
   - Query tags are accessible via the class base.

   51.1 (11.12.2007)
   - Initial revision.

DESCRIPTION

   The class decodes PNG pictures using png.library.
   An object of png.decoder class has two ports: port 0 is an input
   accepting MMF_VIDEO_PNG format, port 1 is an output producing
   MMFC_VIDEO_ARGB32 format. The class is a direct subclass of
   multimedia.class.

NEW ATTRIBUTES

   Attributes applicability:
     I - may be set at creation time.
     S - may be set on an existing object.
     G - may be get from an object.
     P - may be set for an object's port.
     Q - may be queried from an object's port.

   MMA_Video_Height         (V50) [..G.Q], ULONG
   MMA_Video_Width          (V50) [..G.Q], ULONG
   MMA_Video_BitsPerPixel   (V50) [..G.Q], ULONG
   MMA_Video_UseAlpha       (V50) [..G.Q], BOOL

NEW METHODS

   MMM_Pull(port, buffer, length)  (V50)