Apng_amiga

apng.hwp
========

This plugin enables Hollywood to load and save animations in the APNG format
(Animated Portable Network Graphics). The great advantage of the APNG format
is that it supports animations that use alpha channel transparency. Neither the
IFF ANIM nor the GIF ANIM formats support alpha channel transparency.
Furthermore,
APNG can also handle true colour frame data. A rival format to APNG is the MNG
format but APNG was chosen because more applications support it.

Once apng.hwp is installed, Hollywood will 'automagically' be able to open
APNG animations. To save animations in the APNG format, use the new saver
constant #ANMFMT_APNG which will be registered by this plugin. Here's an
example how to save an animation in the APNG format:

    BeginAnimStream(1, "test.apng", width, height, #ANMFMT_APNG)
    For Local k = 1 to numframes Do WriteAnimFrame(1, ...)
    FinishAnimStream(1)

The APNG plugin supports palette and true colour frame data. If you set
Hollywood's "LoadPalette" tag to TRUE in commands like OpenAnim() or ()ANIM,
the APNG plugin will load the animation in palette mode. You can also set
the "LoadTransparency" tag to TRUE to load a transparent pen in case the
animation is palette-based. If the animation uses true colour frame data
and an alpha channel, set the "LoadAlpha" tag to TRUE to load the alpha
channel transparency.

When saving an animation using SaveAnim() or BeginAnimStream() the APNG
plugin will create either a palette-based or a true colour APNG animation
file for you, depending on whether you pass palette or true colour data
for the individual frames.


History
=======

Version 1.3:    (09-Dec-23)
- Fix: APNG files without transparency channel weren't loaded correctly
(reported
  by Juan Carlos Herran Martin)

Version 1.2:    (18-May-23)
- Change: Amiga installer will now also copy the plugins for all platforms to
the
  linker plugins directory so that they can be easily linked to executables
- Change: Plugin uses Hollywood's inbuilt zlib now on Amiga and Windows and the
  system's zlib on all other platforms; this reduces the binary size by ~50kb;
  it also means that the plugin requires at least Hollywood 6.0 now
- Change [iOS]: Added arm64 build for the iOS simulator and removed x86 build
for
  the iOS simulator because the iOS simulator is no longer compatible with x86
- Change [Android]: Removed build for 32-bit softfloat ARM; nobody uses this any
  longer these days
- New [macOS]: Added build for macOS arm64 (Apple Silicon) 
- Change: Changed display name to "APNG" instead of "PNG Anim"
- New: Added support for Hollywood 10's ability to get the anim format name;
when
  querying #ATTRFORMAT for anims loaded using the plugin you'll get "APNG" now
- New: Plugin supports Hollywood 10's user tag interface for file adapters now;
  all user tags will be forwarded to the corresponding file adapters now 
- New: Added support for creating palette-based APNG animations; note that this
  is only supported if at least Hollywood 9.0 is installed; also note that APNG
  animations do not support frame-based palettes but there must be a single
  global palette that is used by all frames; pen-based transparency is also
  supported when creating palette-based APNG animations
- New: Hollywood 9.0's new "LoadPalette" tag is now supported
- Fix: Fixed APNG saver for Hollywood 9.0
- New: Hollywood's "LoadTransparency" tag is now supported too

Version 1.1:    (01-Jul-15)
- New [Linux]: Added build for Linux ARM
- Fix [Linux/MacOS]: Plugin is now compiled as position-independent code (PIC)
- Fix [OS3]: FPU version will cleanly exit now in case there is no FPU
- New: Added file types information for Hollywood 5.3

Version 1.0:    (07-Feb-13)
- First release 


Copyright
=========

This plugin was written by Andreas Falkenhahn <andreas()airsoftsoftwair.de>
See the COPYING file in this package for conditions concerning distribution
of this plugin. Visit http://www.hollywood-mal.com/ for more information
on Hollywood and more plugins.