Thread-safe singleton to hold a shared QR code BufferedImage. More...

Collaboration diagram for fr.softsf.canscan.ui.EncodedImage:

Public Member Functions
void	drawFinderPatterns (Graphics2D g, int matrixWidth, CommonFields config)
	Renders the three QR code finder patterns at the corners using the specified style.

void	drawLogoIfPresent (Graphics2D g, CommonFields config) throws IOException
	Draws the logo at the center of the QR code if a valid logo file is provided.

void	drawSquareFinderPatternAtPixel (Graphics2D g, double x, double y, double diameter, Color qrColor, Color bgColor)
	Draws a standard square QR code finder pattern at the specified pixel coordinates.

void	freeQrOriginal ()
	Releases the current QR code image and its resources.

BufferedImage	generateImage (String data, CommonFields config) throws WriterException, IOException
	Generates a QR code image with optional logo and styling.

BufferedImage	getQrOriginal ()
	Retrieves a defensive copy of the QR code image.

void	updateQrOriginal (BufferedImage newImage)
	Updates the QR code image using a defensive copy.

Private Member Functions
BufferedImage	createDefensiveCopy (BufferedImage sourceImage)
	Creates a defensive copy of the source image.

BitMatrix	createMatrix (String text, int margin) throws WriterException
	Creates a QR code matrix for the given text.

void	drawModule (Graphics2D g, int x, int y, double moduleSizeX, double moduleSizeY, CommonFields config)
	Draws a single QR code module at the specified coordinates with configured size and shape.

void	drawModules (Graphics2D g, BitMatrix matrix, CommonFields config)
	Renders all QR code modules onto the provided graphics context.

void	drawRoundedFinderPatternAtPixel (Graphics2D g, double x, double y, double diameter, Color qrColor, Color bgColor)
	Draws a QR code finder pattern with rounded corners at the specified pixel coordinates.

long	estimateImageMemoryMB (int size)
	Estimates the memory required to create a BufferedImage.

void	fillBackground (Graphics2D g, int size, Color bgColor)
	Fills the entire QR code area with the specified background color.

long	getAvailableMemoryMB ()
	Gets the available memory in the JVM with safety margin for image generation.

boolean	isInBottomLeftPattern (int x, int y, int matrixHeight, int margin)
	Checks if coordinates are within the bottom-left position pattern.

boolean	isInPositionPattern (int x, int y, int matrixWidth, int matrixHeight, int margin)
	Determines whether the given coordinates fall within any of the three QR code position patterns.

boolean	isInTopLeftPattern (int x, int y, int margin)
	Checks if coordinates are within the top-left position pattern.

boolean	isInTopRightPattern (int x, int y, int matrixWidth, int margin)
	Checks if coordinates are within the top-right position pattern.

boolean	shouldSkipModule (int x, int y, BitMatrix matrix, ModuleContext ctx)
	Determines whether a QR code module should be skipped during rendering.

void	validateMemoryForImageSize (int size)
	Validates that sufficient memory is available to generate a square image of the given size.

Private Attributes
final Object	imageLock = new Object()

BufferedImage	qrOriginal

Static Private Attributes
static final int	AVAILABLE_MEMORY_TO_GENERATE_IMAGE = 50

static final String	BG_COLOR = "bgColor"

static final int	BYTES_PER_KILOBYTE = 1024

static final String	CONFIG = "config"

static final double	DEFAULT_GAP_BETWEEN_LOGO_AND_MODULES = 0.9

static final String	DRAW_MODULES = "drawModules"

static final String	DRAW_ROUNDED_FINDER_PATTERN_AT_PIXEL

static final String	DRAW_SQUARE_FINDER_PATTERN_AT_PIXEL

static final String	GENERATE_QR_CODE_IMAGE = "generateQrCodeImage"

static final String	MATRIX = "matrix"

static final String	SHOULD_SKIP_MODULE = "shouldSkipModule"

Detailed Description

Thread-safe singleton to hold a shared QR code BufferedImage.

All access is synchronized for thread safety.

Member Function Documentation

◆ createDefensiveCopy()

BufferedImage fr.softsf.canscan.ui.EncodedImage.createDefensiveCopy ( BufferedImage sourceImage )

private

Creates a defensive copy of the source image.

Parameters

sourceImage The image to copy (must not be null).

Returns: A new BufferedImage instance with the content of the source image.

◆ createMatrix()

BitMatrix fr.softsf.canscan.ui.EncodedImage.createMatrix	(	String	text,
		int	margin ) throws WriterException

private

Creates a QR code matrix for the given text.

Parameters

text	The string to encode in the QR code.
margin	The outer margin of the QR code in modules.

Returns: A BitMatrix representing the encoded QR code.

Exceptions

WriterException If encoding fails.

◆ drawFinderPatterns()

void fr.softsf.canscan.ui.EncodedImage.drawFinderPatterns	(	Graphics2D	g,
		int	matrixWidth,
		CommonFields	config )

Renders the three QR code finder patterns at the corners using the specified style.

Parameters

g	The graphics context for rendering.
matrixWidth	Width of the QR code matrix.
config	Configuration containing size, colors, module shape, and margin.

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◆ drawLogoIfPresent()

void fr.softsf.canscan.ui.EncodedImage.drawLogoIfPresent	(	Graphics2D	g,
		CommonFields	config ) throws IOException

Draws the logo at the center of the QR code if a valid logo file is provided.

The logo is scaled to fit within 90% of the designated white box area, which is determined by the QR code size and configured image ratio.

Parameters

g	The Graphics2D context used for rendering the QR code.
config	QR code configuration containing size, logo file, and image ratio.

Exceptions

IOException If reading the logo file fails or the file is not a valid image.

◆ drawModule()

void fr.softsf.canscan.ui.EncodedImage.drawModule	(	Graphics2D	g,
		int	x,
		int	y,
		double	moduleSizeX,
		double	moduleSizeY,
		CommonFields	config )

private

Draws a single QR code module at the specified coordinates with configured size and shape.

Supports square or rounded modules depending on configuration.

Parameters

g	the graphics context used for rendering
x	the module's x-coordinate in the matrix
y	the module's y-coordinate in the matrix
moduleSizeX	width of the module in pixels
moduleSizeY	height of the module in pixels
config	the QR code configuration

◆ drawModules()

void fr.softsf.canscan.ui.EncodedImage.drawModules	(	Graphics2D	g,
		BitMatrix	matrix,
		CommonFields	config )

private

Renders all QR code modules onto the provided graphics context.

Modules that are part of finder patterns or the central logo area are skipped. Supports rounded or square modules according to configuration.

Parameters

g	the graphics context used for drawing
matrix	the QR code bit matrix representing module positions
config	the QR code configuration including size, colors, module shape, margin, and logo ratio

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◆ drawRoundedFinderPatternAtPixel()

void fr.softsf.canscan.ui.EncodedImage.drawRoundedFinderPatternAtPixel	(	Graphics2D	g,
		double	x,
		double	y,
		double	diameter,
		Color	qrColor,
		Color	bgColor )

private

Draws a QR code finder pattern with rounded corners at the specified pixel coordinates.

Parameters

g	Graphics2D context to draw on.
x	X-coordinate of the top-left corner.
y	Y-coordinate of the top-left corner.
diameter	Diameter of the finder pattern.
qrColor	Color of the QR modules.
bgColor	Background color inside the pattern.

◆ drawSquareFinderPatternAtPixel()

void fr.softsf.canscan.ui.EncodedImage.drawSquareFinderPatternAtPixel	(	Graphics2D	g,
		double	x,
		double	y,
		double	diameter,
		Color	qrColor,
		Color	bgColor )

Draws a standard square QR code finder pattern at the specified pixel coordinates.

Parameters

g	Graphics2D context to draw on.
x	X-coordinate of the top-left corner.
y	Y-coordinate of the top-left corner.
diameter	Diameter of the finder pattern.
qrColor	Color of the QR modules.
bgColor	Background color inside the pattern.

◆ estimateImageMemoryMB()

long fr.softsf.canscan.ui.EncodedImage.estimateImageMemoryMB ( int size )

private

Estimates the memory required to create a BufferedImage.

Parameters

size	The width and height of the square image.

Returns: Estimated memory in megabytes.

◆ fillBackground()

void fr.softsf.canscan.ui.EncodedImage.fillBackground	(	Graphics2D	g,
		int	size,
		Color	bgColor )

private

Fills the entire QR code area with the specified background color.

Parameters

g	The graphics context used for drawing.
size	The width and height of the QR code area in pixels.
bgColor	The background color to fill.

◆ freeQrOriginal()

void fr.softsf.canscan.ui.EncodedImage.freeQrOriginal ( )

Releases the current QR code image and its resources.

◆ generateImage()

BufferedImage fr.softsf.canscan.ui.EncodedImage.generateImage	(	String	data,
		CommonFields	config ) throws WriterException, IOException

Generates a QR code image with optional logo and styling.

Uses ZXing with high error correction to ensure scanability even when a logo is embedded. Visual properties such as size, colors, margin, and module style are applied from the given configuration.

Parameters

data	the string to encode in the QR code
config	configuration including size, colors, margin, module style, and optional logo

Returns: a BufferedImage containing the generated QR code

Exceptions

WriterException	if encoding the data fails
IOException	if reading the logo file fails
OutOfMemoryError	if the requested size exceeds available memory

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◆ getAvailableMemoryMB()

long fr.softsf.canscan.ui.EncodedImage.getAvailableMemoryMB ( )

private

Gets the available memory in the JVM with safety margin for image generation.

Returns: Available memory in megabytes, minus the reserved safety margin. Returns 0 if not enough memory is available.

◆ getQrOriginal()

BufferedImage fr.softsf.canscan.ui.EncodedImage.getQrOriginal ( )

Retrieves a defensive copy of the QR code image.

Synchronized. Returns a copy to prevent external mutation of the internal state.

Returns: A defensive copy of the image, or null.

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◆ isInBottomLeftPattern()

boolean fr.softsf.canscan.ui.EncodedImage.isInBottomLeftPattern	(	int	x,
		int	y,
		int	matrixHeight,
		int	margin )

private

Checks if coordinates are within the bottom-left position pattern.

Parameters

x	X-coordinate
y	Y-coordinate
matrixHeight	Height of the QR matrix
margin	QR code margin

Returns: true if inside bottom-left pattern; false otherwise

◆ isInPositionPattern()

boolean fr.softsf.canscan.ui.EncodedImage.isInPositionPattern	(	int	x,
		int	y,
		int	matrixWidth,
		int	matrixHeight,
		int	margin )

private

Determines whether the given coordinates fall within any of the three QR code position patterns.

Parameters

x	X-coordinate in the QR matrix.
y	Y-coordinate in the QR matrix.
matrixWidth	Width of the QR matrix.
matrixHeight	Height of the QR matrix.
margin	QR code margin in modules.

Returns: true if the coordinate is inside a position pattern; false otherwise.

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◆ isInTopLeftPattern()

boolean fr.softsf.canscan.ui.EncodedImage.isInTopLeftPattern	(	int	x,
		int	y,
		int	margin )

private

Checks if coordinates are within the top-left position pattern.

Parameters

x	X-coordinate
y	Y-coordinate
margin	QR code margin

Returns: true if inside top-left pattern; false otherwise

◆ isInTopRightPattern()

boolean fr.softsf.canscan.ui.EncodedImage.isInTopRightPattern	(	int	x,
		int	y,
		int	matrixWidth,
		int	margin )

private

Checks if coordinates are within the top-right position pattern.

Parameters

x	X-coordinate
y	Y-coordinate
matrixWidth	Width of the QR matrix
margin	QR code margin

Returns: true if inside top-right pattern; false otherwise

◆ shouldSkipModule()

boolean fr.softsf.canscan.ui.EncodedImage.shouldSkipModule	(	int	x,
		int	y,
		BitMatrix	matrix,
		ModuleContext	ctx )

private

Determines whether a QR code module should be skipped during rendering.

A module is skipped if it is unset, part of a finder pattern, or overlaps the central logo area.

Parameters

x	the module's x-coordinate in the QR matrix
y	the module's y-coordinate in the QR matrix
matrix	the QR code bit matrix
ctx	the module context containing configuration, matrix dimensions, and logo box

Returns: true if the module should be skipped, false otherwise

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◆ updateQrOriginal()

void fr.softsf.canscan.ui.EncodedImage.updateQrOriginal ( BufferedImage newImage )

Updates the QR code image using a defensive copy.

Stores a copy of the input (input defense).

Parameters

newImage The new image; null clears the current image.

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◆ validateMemoryForImageSize()

void fr.softsf.canscan.ui.EncodedImage.validateMemoryForImageSize ( int size )

private

Validates that sufficient memory is available to generate a square image of the given size.

Applies a hard limit of 200M px and ensures a minimum memory margin before allocation.

Parameters

size	the width and height of the square image in pixels

Exceptions

OutOfMemoryError if the image exceeds pixel limits or available memory is insufficient

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Member Data Documentation

◆ AVAILABLE_MEMORY_TO_GENERATE_IMAGE

final int fr.softsf.canscan.ui.EncodedImage.AVAILABLE_MEMORY_TO_GENERATE_IMAGE = 50

staticprivate

◆ BG_COLOR

final String fr.softsf.canscan.ui.EncodedImage.BG_COLOR = "bgColor"

staticprivate

◆ BYTES_PER_KILOBYTE

final int fr.softsf.canscan.ui.EncodedImage.BYTES_PER_KILOBYTE = 1024

staticprivate

◆ CONFIG

final String fr.softsf.canscan.ui.EncodedImage.CONFIG = "config"

staticprivate

◆ DEFAULT_GAP_BETWEEN_LOGO_AND_MODULES

final double fr.softsf.canscan.ui.EncodedImage.DEFAULT_GAP_BETWEEN_LOGO_AND_MODULES = 0.9

staticprivate

◆ DRAW_MODULES

final String fr.softsf.canscan.ui.EncodedImage.DRAW_MODULES = "drawModules"

staticprivate

◆ DRAW_ROUNDED_FINDER_PATTERN_AT_PIXEL

final String fr.softsf.canscan.ui.EncodedImage.DRAW_ROUNDED_FINDER_PATTERN_AT_PIXEL

staticprivate

Initial value:

=

"drawRoundedFinderPatternAtPixel"

◆ DRAW_SQUARE_FINDER_PATTERN_AT_PIXEL

final String fr.softsf.canscan.ui.EncodedImage.DRAW_SQUARE_FINDER_PATTERN_AT_PIXEL

staticprivate

Initial value:

=

"drawSquareFinderPatternAtPixel"

◆ GENERATE_QR_CODE_IMAGE

final String fr.softsf.canscan.ui.EncodedImage.GENERATE_QR_CODE_IMAGE = "generateQrCodeImage"

staticprivate

◆ imageLock

final Object fr.softsf.canscan.ui.EncodedImage.imageLock = new Object()

private

◆ MATRIX

final String fr.softsf.canscan.ui.EncodedImage.MATRIX = "matrix"

staticprivate

◆ qrOriginal

BufferedImage fr.softsf.canscan.ui.EncodedImage.qrOriginal

private

◆ SHOULD_SKIP_MODULE

final String fr.softsf.canscan.ui.EncodedImage.SHOULD_SKIP_MODULE = "shouldSkipModule"

staticprivate

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

src/main/java/fr/softsf/canscan/ui/EncodedImage.java

Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Function Documentation

◆ createDefensiveCopy()

◆ createMatrix()

◆ drawFinderPatterns()

◆ drawLogoIfPresent()

◆ drawModule()

◆ drawModules()

◆ drawRoundedFinderPatternAtPixel()

◆ drawSquareFinderPatternAtPixel()

◆ estimateImageMemoryMB()

◆ fillBackground()

◆ freeQrOriginal()

◆ generateImage()

◆ getAvailableMemoryMB()

◆ getQrOriginal()

◆ isInBottomLeftPattern()

◆ isInPositionPattern()

◆ isInTopLeftPattern()

◆ isInTopRightPattern()

◆ shouldSkipModule()

◆ updateQrOriginal()

◆ validateMemoryForImageSize()

Member Data Documentation

◆ AVAILABLE_MEMORY_TO_GENERATE_IMAGE

◆ BG_COLOR

◆ BYTES_PER_KILOBYTE

◆ CONFIG

◆ DEFAULT_GAP_BETWEEN_LOGO_AND_MODULES

◆ DRAW_MODULES

◆ DRAW_ROUNDED_FINDER_PATTERN_AT_PIXEL

◆ DRAW_SQUARE_FINDER_PATTERN_AT_PIXEL

◆ GENERATE_QR_CODE_IMAGE

◆ imageLock

◆ MATRIX

◆ qrOriginal

◆ SHOULD_SKIP_MODULE