JPEGParser< RGB_T > Class Template Reference

Decodes baseline JPEG images into a TinyGPU ISurface, using pschatzmann/TinyJPEG (https://github.com/pschatzmann/TinyJPEG) as the underlying decoder. More...

#include <JPEGParser.h>

Collaboration diagram for JPEGParser< RGB_T >:

Public Member Functions
	JPEGParser (ISurface< RGB_T > &target)
void	setSwapBytes (bool swap)
void	setScale (uint8_t scale)
	Sets the output reduction factor: 1 (full size), 2, 4, or 8.
bool	decode (const uint8_t *data, size_t size)
template<typename FileT >
bool	decode (FileT &file)
const char *	errorMessage () const
	Returns the latest error message, if any.

Protected Member Functions
bool	setError (const char *message)
bool	checkResult (JRESULT result)

Static Protected Member Functions
static bool	onBlock (tinyjpeg::TinyJPEGDecoder &decoder, int16_t x, int16_t y, uint16_t w, uint16_t h, uint16_t *data)

Protected Attributes
ISurface< RGB_T > &	target_
tinyjpeg::TinyJPEGDecoder	decoder_
const char *	errorMessage_ = nullptr

Detailed Description

template<typename RGB_T = RGB565>
class tinygpu::JPEGParser< RGB_T >

Decodes baseline JPEG images into a TinyGPU ISurface, using pschatzmann/TinyJPEG (https://github.com/pschatzmann/TinyJPEG) as the underlying decoder.

TinyJPEG is a separate, optional Arduino/CMake library - install it alongside TinyGPU and #include <TinyGPU/IO/JPEGParser.h> explicitly (this header is not pulled in by TinyGPU.h) to opt in to JPEG support.

TinyJPEG streams decoded pixels one MCU block at a time rather than requiring memory for the whole decoded frame, so decode() resizes the target surface once (from the JPEG's own header) and then just fans each block out to setPixel() as it arrives - no intermediate frame buffer beyond the target surface itself.

Constructor & Destructor Documentation

JPEGParser()

JPEGParser ( ISurface< RGB_T > &  target )

inlineexplicit

Member Function Documentation

checkResult()

bool checkResult ( JRESULT  result )

inlineprotected

decode() [1/2]

bool decode ( const uint8_t *  data, size_t  size  )

inline

Decodes a JPEG held entirely in memory into the target surface at (0, 0). Resizes the target surface to the JPEG's own dimensions first.

decode() [2/2]

bool decode ( FileT &  file )

inline

Decodes a JPEG read from any file-like object (Arduino's fs::File, SD's File, or anything else exposing available()/read()/position()/ seek() - see TinyJPEG's docs/decoding.md) into the target surface at (0, 0). Resizes the target surface to the JPEG's own dimensions first. file is read from its current position and left wherever the decode stopped; this method rewinds to that starting position only between reading the header and decoding the pixels.

errorMessage()

const char * errorMessage ( ) const

inline

Returns the latest error message, if any.

onBlock()

static bool onBlock ( tinyjpeg::TinyJPEGDecoder &  decoder, int16_t  x, int16_t  y, uint16_t  w, uint16_t  h, uint16_t *  data  )

inlinestaticprotected

setError()

bool setError ( const char *  message )

inlineprotected

setScale()

void setScale ( uint8_t  scale )

inline

Sets the output reduction factor: 1 (full size), 2, 4, or 8.

setSwapBytes()

void setSwapBytes ( bool  swap )

inline

Overrides the byte-swap behavior set in the constructor (see its comment) - some panels/wiring need the opposite of the true default that's otherwise correct.

Member Data Documentation

decoder_

tinyjpeg::TinyJPEGDecoder decoder_

protected

errorMessage_

const char* errorMessage_ = nullptr

protected

target_

ISurface<RGB_T>& target_

protected

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The documentation for this class was generated from the following file:

• src/TinyGPU/IO/JPEGParser.h