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APNG Specification: Difference between revisions
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fix typos
Herbyderby (talk | contribs) m (Replace "placeholder image" with "default image") |
Herbyderby (talk | contribs) m (fix typos) |
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== Terminology == | == Terminology == | ||
The "default image" is the image described by the standard `IDAT` chunks, and is the image that displayed by decoders that do not support APNG. | The "default image" is the image described by the standard `IDAT` chunks, and is the image that is displayed by decoders that do not support APNG. | ||
The "canvas" is the area on the output device on which the frames are to be displayed. The contents of the canvas are not necessarily available to the decoder. As per the PNG Specification, if a `bKGD` chunk exists it may be used to fill the canvas if there is no preferrable background. | The "canvas" is the area on the output device on which the frames are to be displayed. The contents of the canvas are not necessarily available to the decoder. As per the PNG Specification, if a `bKGD` chunk exists it may be used to fill the canvas if there is no preferrable background. | ||
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* Added `aCTL`, `fdAT`, `fcTL` chunk descriptions as per the latest png-list discussion | * Added `aCTL`, `fdAT`, `fcTL` chunk descriptions as per the latest png-list discussion | ||
* Added section 4, "Interactions with other PNG chunks"; described global and local palettes and | * Added section 4, "Interactions with other PNG chunks"; described global and local palettes and transparency | ||
transparency | |||
* Changed `oFFs` chunk section to refer to more general chunks | * Changed `oFFs` chunk section to refer to more general chunks | ||
* Updated `aDAT` description to indicate that all frames must either be in a single chunk, or that the first | * Updated `aDAT` description to indicate that all frames must either be in a single chunk, or that the first chunk must have empty data. | ||
chunk must have empty data. | |||
* Added notice that each frame's region (x,y,width,height) must lie completely within the parent PNG canvas | * Added notice that each frame's region (x,y,width,height) must lie completely within the parent PNG canvas | ||
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* Changed dispose_op to render_op; added disposal description; added BLEND flag | * Changed dispose_op to render_op; added disposal description; added BLEND flag | ||
* Changed delay_time to a delay numerator and denominator, for specifying delays that don't into integer | * Changed delay_time to a delay numerator and denominator, for specifying delays that don't into integer numbers of milliseconds. | ||
numbers of milliseconds. | |||
* Added note to clarify that palette animation is not supported. | * Added note to clarify that palette animation is not supported. | ||