[−][src]Module png_pong::chunk
Low-level PNG API
A PNG file consists of a sequence of Chunk
s in a
specific order.
PNG Chunk Order
Key
- Required - Count must be exactly one.
- Optional - Count must be exactly one or zero.
- Multiple - Count can be any number, including zero.
Order
The PNG/APNG chunk order must be as follows:
- Required
ImageHeader
"IHDR" - In any order:
- Optional
Chromaticities
- Optional
Gamma
"gAMA" - Optional
ColorProfile
"iCCP" - Optional
SignificantBits
"sBIT" - Optional
SRgb
"sRGB" - Optional
Physical
"pHYs" - Multiple
SuggestedPalette
"sPLT" - Optional
Time
"tIME" (If didn't appear earlier) - Multiple
InternationalText
"iTXt" - Multiple
Text
"tEXt" - Multiple
CompressedText
"zTXt" - Optional
AnimationControl
"acTL" (APNG) - Optional
FrameControl
"fcTL" (APNG) - Optional
ImageOffset
"oFFs" (Extension) - Optional
PixelCalibration
"pCAL" (Extension) - Optional
SubjectPhysical
"sCAL" (Extension) - Multiple
GifGraphicControlExt
"gIFg" (Extension) - Multiple
GifApplicationExt
"gIFx" (Extension)
- Optional
- Optional
Palette
"PLTE" - In any order:
- Optional
Background
"bKGD" - Optional
PaletteHistogram
"hIST" - Optional
Transparency
"tRNS" - Optional
Physical
"pHYs" (If didn't appear before PLTE) - Multiple
SuggestedPalette
"sPLT" - Optional
Time
"tIME" (If didn't appear earlier) - Multiple
InternationalText
"iTXt" - Multiple
Text
"tEXt" - Multiple
CompressedText
"zTXt" - Optional
AnimationControl
"acTL" (APNG, If didn't appear earlier) - Optional
FrameControl
"fcTL" (APNG, If didn't appear earlier) - Optional
ImageOffset
"oFFs" (Extension, If didn't appear earlier) - Optional
PixelCalibration
"pCAL" (Extension, If didn't appear earlier) - Optional
SubjectPhysical
"sCAL" (Extension, If didn't appear earlier) - Multiple
GifGraphicControlExt
"gIFg" (Extension) - Multiple
GifApplicationExt
"gIFx" (Extension)
- Optional
- Multiple
ImageData
"IDAT" - In any order:
- Optional
Time
"tIME" (If didn't appear earlier) - Multiple
InternationalText
"iTXt" - Multiple
Text
"tEXt" - Multiple
CompressedText
"zTXt" - Multiple
FrameControl
"fcTL" (APNG) - Multiple
FrameData
"fdAT" (APNG, must be somewhere after "fcTL") - Multiple
GifGraphicControlExt
"gIFg" (Extension) - Multiple
GifApplicationExt
"gIFx" (Extension)
- Optional
- Required
ImageEnd
"IEND"
Structs
CompressedText | Compressed Text Chunk Data (zTXt) |
ImageData | Image Data Chunk Data (IDAT) |
ImageEnd | Image End Chunk Data (IEND) |
ImageHeader | Image Header Chunk Data (IHDR) |
InternationalText | International Text Chunk Data (iTXt) |
Palette | Palette Chunk Data (PLTE) |
Physical | Physical dimensions chunk (pHYs) |
Text | Non-International Text Chunk Data (tEXt and zTXt) |
Time | Time chunk (tIME) |
Enums
Background | Suggested background color chunk (bKGD) |
Chunk | A chunk within a PNG file. |
ColorType | Standard PNG color types. |
Transparency | Alpha Palette Chunk Data (tRNS) |