PNGImage¶

constructor¶

PNGImage(int iWidth, int iHeight, int iBitDepth=8, int iColorType=PNG_COLOR_TYPE_RGB_ALPHA);
PNGImage();

iWidth

Width of image to create.

iHeight

Height of image to create.

iBitDepth

Number of bits to encode each channel:

8 gives the best color resolution (8 bit red, 8 bit green, 8bit blue, 8 bit alpha).

iColorType

Color type of image. The following constants can be found in png.h, the header file for the png library:

The constructor with no arguments is called when one intends to read a png file.

destructor¶

virtual ~PNGImage();

The destructor deletes various arrays and destroys some PNG-related structures.

createPNGFromData¶

bool createPNGFromData(double ***aadData, const std::string sOutputFile);

bool createPNGFromData(uchar  **aaucData, const std::string sOutputFile);

aadData

An array holding the rgba values as double ( aaData[13][25][1] : green value for pixel (13,25)).

aaucData

An array holding the rgba values as uchar. The actual array format is iH x 4*iW, where the 4 rgba uchar values are written one after the other (aucData[13][4*25]: red value for pixel (13,25), aucData[13][4*25+2]: blue value for pixel (13,25)).

Creates PNG data from the data provided and writes it to the output file.

isInitialized¶

bool isInitialized();

Returns true if the data to be written has been properly initialized.

setPalette¶

void setPalette(uchar **pPaletteEntries, int iNumPaletteEntries, bool bUseAlpha=false);

Set a color palette with colors to be used (the PNG array values are indexes into the palette).

readPNGFile¶

bool readPNGFile(const std::string sInputFile);

Reads the PNG data from the PNG file sInputFile. The data can be obtained by the methods getRow() and getRows().

image info¶

int getWidth();
int getHeight();
int getColorType();
int getBitDepth();
int getByteWidth();
int getNumChannels();
int getText(char ***ppKeys, char ***ppValues);

These methods return information about the current PNG data. Usually called after reading a PNG file with readPNGFile().

getRow¶

uchar *getRow(int iIndex);

iIndex

Number of the row to return.

Returns the specified row of the current image data.

getRows¶

uchar **getRows();

Returns the entire image data.

setRow¶

void setRow(int iIndex, uchar *ucRow);
void setRow(int iIndex, int *piRow);

iIndex

Number of the row to replace.

ucRow

uchar color values for the row to be replaced.

piRow

int color values for the row to be replaced.