C++ error: no match for call to ‘(RgbImage) (int&, int&)’ - c++

Question

The pseudo code I'm trying to follow for this implementation:
for (int u = 0; u < uMax; u++)
{ for (int v = 0; v < vMax; v++)
{ float x = f_x(u, v);
float y = f_y(u, v);
dstImage(x, y) = srcImage(u, v);
}
}
The scaling function I'm trying to implement the above code with. I iterate over each pixel just as I did to change the r,g,b, but I'm having issues changing the value of the x. I've implemented code for this to change the r,g,b of the image but I would now like to be able to scale the x of the image by a factor of 2. This is the attempt to scale x the in the same way as changing r,g,b.
void scale()
{
RgbImage theTexMap( filename ); // loaded from some file name
//RgbImage destination;
double r, g, b; // variables to store the different colours
float u, v;
for (int x = 0; x < theTexMap.GetNumRows(); x++)
{ for (int y = 0; y < theTexMap.GetNumCols(); y++)
{ theTexMap.GetRgbPixel(x, y, &r, &g, &b); //this successfully allows me to change the r,g,b values
u = x * 2;
v = y;
//cout << x <<endl;
//cout << y << " " << endl;
//cout << " " <<endl;
destination.SetRgbPixelf(u, v, r, g, b); //allows me to set r,g,b values, fails with the x,y.
}
}
updateTexture(&destination, modifiedID);
}
According to the Pseudo code I'm trying to follow, it should be more like this. (changed inside of for loops and used u,v iteration)
void scale()
{
RgbImage theTexMap( filename ); // loaded from some file name
//RgbImage destination;
double r, g, b; // variables to store the different colours
float x, y;
for (int u = 0; u < theTexMap.GetNumRows(); u++)
{ for (int v = 0; v < theTexMap.GetNumCols(); v++)
{ x = u * 2;
y = v;
//cout << x <<endl;
//cout << y << " " << endl;
//cout << " " <<endl;
theTexMap(x,y) = theTexMap(u,v)
}
}
updateTexture(&theTexMap, modifiedID);
}
Now because I don't really understand the pseudo code for that last line, I get this error message when I call it in my implementation. The error message I receive.
error: no match for call to ‘(RgbImage) (float&, float&)’
theTexMap(x,y) = theTexMap(u,v);
Well now your saying, I don't know what RgbImage (the type of theTexMap) is you dummy. So here's it's class. Should I be using it in this case like the above? Or how should I follow that pseudo code to get my desired factor of 2 scaling?
#include "RgbImage.h"
#ifndef RGBIMAGE_DONT_USE_OPENGL
#ifdef _WIN32
#include <windows.h>
#endif
#include "GL/gl.h"
#endif
RgbImage::RgbImage( int numRows, int numCols )
{
NumRows = numRows;
NumCols = numCols;
ImagePtr = new unsigned char[NumRows*GetNumBytesPerRow()];
if ( !ImagePtr ) {
fprintf(stderr, "Unable to allocate memory for %ld x %ld bitmap.\n",
NumRows, NumCols);
Reset();
ErrorCode = MemoryError;
}
// Zero out the image
unsigned char* c = ImagePtr;
int rowLen = GetNumBytesPerRow();
for ( int i=0; i<NumRows; i++ ) {
for ( int j=0; j<rowLen; j++ ) {
*(c++) = 0;
}
}
}
bool RgbImage::LoadBmpFile( const char* filename )
{
Reset();
FILE* infile = fopen( filename, "rb" ); // Open for reading binary data
if ( !infile ) {
fprintf(stderr, "Unable to open file: %s\n", filename);
ErrorCode = OpenError;
return false;
}
bool fileFormatOK = false;
int bChar = fgetc( infile );
int mChar = fgetc( infile );
if ( bChar=='B' && mChar=='M' ) { // If starts with "BM" for "BitMap"
skipChars( infile, 4+2+2+4+4 ); // Skip 4 fields we don't care about
NumCols = readLong( infile );
NumRows = readLong( infile );
skipChars( infile, 2 ); // Skip one field
int bitsPerPixel = readShort( infile );
skipChars( infile, 4+4+4+4+4+4 ); // Skip 6 more fields
if ( NumCols>0 && NumCols<=100000 && NumRows>0 && NumRows<=100000
&& bitsPerPixel==24 && !feof(infile) ) {
fileFormatOK = true;
}
}
if ( !fileFormatOK ) {
Reset();
ErrorCode = FileFormatError;
fprintf(stderr, "Not a valid 24-bit bitmap file: %s.\n", filename);
fclose ( infile );
return false;
}
// Allocate memory
ImagePtr = new unsigned char[NumRows*GetNumBytesPerRow()];
if ( !ImagePtr ) {
fprintf(stderr, "Unable to allocate memory for %ld x %ld bitmap: %s.\n",
NumRows, NumCols, filename);
Reset();
ErrorCode = MemoryError;
fclose ( infile );
return false;
}
unsigned char* cPtr = ImagePtr;
for ( int i=0; i<NumRows; i++ ) {
int j;
for ( j=0; j<NumCols; j++ ) {
*(cPtr+2) = fgetc( infile ); // Blue color value
*(cPtr+1) = fgetc( infile ); // Green color value
*cPtr = fgetc( infile ); // Red color value
cPtr += 3;
}
int k=3*NumCols; // Num bytes already read
for ( ; k<GetNumBytesPerRow(); k++ ) {
fgetc( infile ); // Read and ignore padding;
*(cPtr++) = 0;
}
}
if ( feof( infile ) ) {
fprintf( stderr, "Premature end of file: %s.\n", filename );
Reset();
ErrorCode = ReadError;
fclose ( infile );
return false;
}
fclose( infile ); // Close the file
return true;
}
short RgbImage::readShort( FILE* infile )
{
// read a 16 bit integer
unsigned char lowByte, hiByte;
lowByte = fgetc(infile); // Read the low order byte (little endian form)
hiByte = fgetc(infile); // Read the high order byte
// Pack together
short ret = hiByte;
ret <<= 8;
ret |= lowByte;
return ret;
}
long RgbImage::readLong( FILE* infile )
{
// Read in 32 bit integer
unsigned char byte0, byte1, byte2, byte3;
byte0 = fgetc(infile); // Read bytes, low order to high order
byte1 = fgetc(infile);
byte2 = fgetc(infile);
byte3 = fgetc(infile);
// Pack together
long ret = byte3;
ret <<= 8;
ret |= byte2;
ret <<= 8;
ret |= byte1;
ret <<= 8;
ret |= byte0;
return ret;
}
void RgbImage::skipChars( FILE* infile, int numChars )
{
for ( int i=0; i<numChars; i++ ) {
fgetc( infile );
}
}
bool RgbImage::WriteBmpFile( const char* filename )
{
FILE* outfile = fopen( filename, "wb" ); // Open for reading binary data
if ( !outfile ) {
fprintf(stderr, "Unable to open file: %s\n", filename);
ErrorCode = OpenError;
return false;
}
fputc('B',outfile);
fputc('M',outfile);
int rowLen = GetNumBytesPerRow();
writeLong( 40+14+NumRows*rowLen, outfile ); // Length of file
writeShort( 0, outfile ); // Reserved for future use
writeShort( 0, outfile );
writeLong( 40+14, outfile ); // Offset to pixel data
writeLong( 40, outfile ); // header length
writeLong( NumCols, outfile ); // width in pixels
writeLong( NumRows, outfile ); // height in pixels (pos for bottom up)
writeShort( 1, outfile ); // number of planes
writeShort( 24, outfile ); // bits per pixel
writeLong( 0, outfile ); // no compression
writeLong( 0, outfile ); // not used if no compression
writeLong( 0, outfile ); // Pixels per meter
writeLong( 0, outfile ); // Pixels per meter
writeLong( 0, outfile ); // unused for 24 bits/pixel
writeLong( 0, outfile ); // unused for 24 bits/pixel
// Now write out the pixel data:
unsigned char* cPtr = ImagePtr;
for ( int i=0; i<NumRows; i++ ) {
// Write out i-th row's data
int j;
for ( j=0; j<NumCols; j++ ) {
fputc( *(cPtr+2), outfile); // Blue color value
fputc( *(cPtr+1), outfile); // Blue color value
fputc( *(cPtr+0), outfile); // Blue color value
cPtr+=3;
}
// Pad row to word boundary
int k=3*NumCols; // Num bytes already read
for ( ; k<GetNumBytesPerRow(); k++ ) {
fputc( 0, outfile ); // Read and ignore padding;
cPtr++;
}
}
fclose( outfile ); // Close the file
return true;
}
void RgbImage::writeLong( long data, FILE* outfile )
{
// Read in 32 bit integer
unsigned char byte0, byte1, byte2, byte3;
byte0 = (unsigned char)(data&0x000000ff); // Write bytes, low order to high order
byte1 = (unsigned char)((data>>8)&0x000000ff);
byte2 = (unsigned char)((data>>16)&0x000000ff);
byte3 = (unsigned char)((data>>24)&0x000000ff);
fputc( byte0, outfile );
fputc( byte1, outfile );
fputc( byte2, outfile );
fputc( byte3, outfile );
}
void RgbImage::writeShort( short data, FILE* outfile )
{
// Read in 32 bit integer
unsigned char byte0, byte1;
byte0 = data&0x000000ff; // Write bytes, low order to high order
byte1 = (data>>8)&0x000000ff;
fputc( byte0, outfile );
fputc( byte1, outfile );
}
/*********************************************************************
* SetRgbPixel routines allow changing the contents of the RgbImage. *
*********************************************************************/
void RgbImage::SetRgbPixelf( long row, long col, double red, double green, double blue )
{
SetRgbPixelc( row, col, doubleToUnsignedChar(red),
doubleToUnsignedChar(green),
doubleToUnsignedChar(blue) );
}
void RgbImage::SetRgbPixelc( long row, long col,
unsigned char red, unsigned char green, unsigned char blue )
{
assert ( row<NumRows && col<NumCols );
unsigned char* thePixel = GetRgbPixel( row, col );
*(thePixel++) = red;
*(thePixel++) = green;
*(thePixel) = blue;
}
unsigned char RgbImage::doubleToUnsignedChar( double x )
{
if ( x>=1.0 ) {
return (unsigned char)255;
}
else if ( x<=0.0 ) {
return (unsigned char)0;
}
else {
return (unsigned char)(x*255.0); // Rounds down
}
}
// Bitmap file format (24 bit/pixel form) BITMAPFILEHEADER
// Header (14 bytes)
// 2 bytes: "BM"
// 4 bytes: long int, file size
// 4 bytes: reserved (actually 2 bytes twice)
// 4 bytes: long int, offset to raster data
// Info header (40 bytes) BITMAPINFOHEADER
// 4 bytes: long int, size of info header (=40)
// 4 bytes: long int, bitmap width in pixels
// 4 bytes: long int, bitmap height in pixels
// 2 bytes: short int, number of planes (=1)
// 2 bytes: short int, bits per pixel
// 4 bytes: long int, type of compression (not applicable to 24 bits/pixel)
// 4 bytes: long int, image size (not used unless compression is used)
// 4 bytes: long int, x pixels per meter
// 4 bytes: long int, y pixels per meter
// 4 bytes: colors used (not applicable to 24 bit color)
// 4 bytes: colors important (not applicable to 24 bit color)
// "long int" really means "unsigned long int"
// Pixel data: 3 bytes per pixel: RGB values (in reverse order).
// Rows padded to multiples of four.
#ifndef RGBIMAGE_DONT_USE_OPENGL
bool RgbImage::LoadFromOpenglBuffer() // Load the bitmap from the current OpenGL buffer
{
int viewportData[4];
glGetIntegerv( GL_VIEWPORT, viewportData );
int& vWidth = viewportData[2];
int& vHeight = viewportData[3];
if ( ImagePtr==0 ) { // If no memory allocated
NumRows = vHeight;
NumCols = vWidth;
ImagePtr = new unsigned char[NumRows*GetNumBytesPerRow()];
if ( !ImagePtr ) {
fprintf(stderr, "Unable to allocate memory for %ld x %ld buffer.\n",
NumRows, NumCols);
Reset();
ErrorCode = MemoryError;
return false;
}
}
assert ( vWidth>=NumCols && vHeight>=NumRows );
int oldGlRowLen;
if ( vWidth>=NumCols ) {
glGetIntegerv( GL_UNPACK_ROW_LENGTH, &oldGlRowLen );
glPixelStorei( GL_UNPACK_ROW_LENGTH, NumCols );
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
// Get the frame buffer data.
glReadPixels( 0, 0, NumCols, NumRows, GL_RGB, GL_UNSIGNED_BYTE, ImagePtr);
// Restore the row length in glPixelStorei (really ought to restore alignment too).
if ( vWidth>=NumCols ) {
glPixelStorei( GL_UNPACK_ROW_LENGTH, oldGlRowLen );
}
return true;
}
#endif // RGBIMAGE_DONT_USE_OPENGL

Answer 1

This expression:
theTexMap(x,y) = theTexMap(u,v);
^^^^^^^^^^^^^^
Is trying to invoke RgbImage::operator()(float, float). That is not a defined operator on your type, hence the error.
I'm guessing the function you want to call is:
theTexMap.GetRgbPixel(u, v, &r, &g, &b);
theTexMap.SetRgbPixelf(x, y, r, g, b);