Picture

kshegunov

sorry i lost you

No, it's me who lost you. I was commenting on @VRonin's remark about your code. However, this:

QColor dominantColor(pixi,point,size);

is neither a function call, nor is it a function declaration. The compiler will interpret this as a variable and will throw "unknown conversion from type X to type Y" errors. You should carefully read @VRonin's link on functions - what is a declaration, what is a definition and how to put it all together. Otherwise you are in for a terrible time, Qt or otherwise.

Kind regards.

Payx

I have to declare my function,
say what they do
and call it.

I say in my .cpp what she does :

QColor dominantColor(const QImage& image, const QPoint& topLeft, const QSize& rectSize) {
// calculate start stop values for the rect
	 const int maxRight = qMin(image.width(), topLeft.x() + rectSize.width());
	const int maxBottom = qMin(image.height(), topLeft.y() + rectSize.height());
	QVector<QColor> coloursList; // this is a list of all colors seen!
	for(int x = topLeft.x(); x < maxRight; ++x) {
		for(int y = topLeft.y(); y < maxBottom; ++y) {
			coloursList << image.pixelColor(x, y); // store all colors seen in this Rect
		}
	}

	// these are functions that count (accumulate) how many times RED, GREEN and blue been used ( using the list from before)
	const qint64 sumRed = std::accumulate(coloursList.constBegin(), coloursList.constEnd(), 0, [](qint64 strt,  const QColor & val)->qint64 {return strt + val.red();});
	const qint64 sumGreen = std::accumulate(coloursList.constBegin(), coloursList.constEnd(), 0, [](qint64 strt, const QColor & val)->qint64 {return strt + val.green();});
	const qint64 sumBlue = std::accumulate(coloursList.constBegin(), coloursList.constEnd(), 0, [](qint64 strt, const QColor & val)->qint64 {return strt + val.blue();});
	// now we check out which is most used
	if(sumRed >= sumGreen  && sumRed >= sumBlue)
		return Qt::red;
	if(sumGreen  >= sumBlue)
		return Qt::green;
	return Qt::blue;
}

I call her and i stock the result in a QColor

void MainWindow::on_push2_clicked()
{
	QPoint point(0,0);
	QSize size(4,4);
	QColor domicolor=dominantColor(pixi,point,size);
// pixi is my image declared in .h with QImage pixi;

}

the problem that i dont know where i can declare her. I try every possibilities

VRonin

ok, now we are making progress. you got what the dominant colour is, now you have to paint the rectange

Payx

@VRonin said in Picture:

ok, now we are making progress. you got what the dominant colour is, now you have to paint the rectange

sorry if don't listen to you very well but

it say that my function isnt declared (dominantColor)

VRonin

http://www.cplusplus.com/doc/tutorial/functions/#declarations

Payx

Okay i fixed it

MainWindow::MainWindow(QWidget *parent) :
	QMainWindow(parent),
	ui(new Ui::MainWindow)
{
		ui->setupUi(this);

}
QColor dominantColor(const QImage& image, const QPoint& topLeft, const QSize& rectSize);
void fillSection(QImage& image, const QPoint& topLeft, const QSize& rectSize, const QColor& colour);

MainWindow::~MainWindow()
{
	delete ui;
}

So now with, fillSection, the problem i have is to declare something who correspond to QColor& colour

i check the code again, and i think its colourList no ?

VRonin

sorry if don't listen to you very well but

No worries, I'm explicitly refraining from giving you the exact answer and rather trying to send you on the right path.

i check the code again, and i think its colourList no ?

Nope, colourList will die: http://www.cplusplus.com/doc/tutorial/namespaces/#scopes

Payx

@VRonin said in Picture:

Nope, colourList will die: http://www.cplusplus.com/doc/tutorial/namespaces/#scopes

Ok i got it, we will put the returned color from QColor dominantColor, thats right ?

VRonin

Getting warmer and warmer

Payx

I got :

QColor domicolor=dominantColor(pixi,point,size);

The returned color is "domicolor", so i put domicolor in :

void fillSection(pixi, point, size, domicolor);

VRonin

sooo close!
http://www.cplusplus.com/doc/tutorial/functions/#void

Payx

I call her with just :

fillSection(pixi,point,size,domicolor);

VRonin

@Payx Bingo!

Payx

I try to change the rectSize with 100 x 100.

my first function is :

void MainWindow::on_push_clicked()
{
	QString fileName = QFileDialog::getOpenFileName(this,
	tr("Open Image"), "/", tr("Image Files (*.png *.jpg *.bmp)"));
	QPixmap pix(fileName);
	ui->label->setPixmap(pix);
	const QSize s = pix.size();
	QImage pixi = QImage(pix.toImage());

	ui->label_2->setText( "Size: " + QString::number(s.width()) +" "+ QString::number(s.height()) );

}

It load an image with an explorer file.

But the picture dont change at all when i click on the push2

VRonin

I did not say you were done, just that you were on the right path.

from the code you posted it's clear you did not grasp scoping 100% so i'll repost the link: http://www.cplusplus.com/doc/tutorial/namespaces/#scopes

pix and pixi die as soon as MainWindow::on_push_clicked() terminates

Payx

@VRonin Yes but in my .h i add QImage pixi thats not correct?

VRonin

I'm surprised your compiler doesn't yell about redefinition (I probably know why but that's not the point here). I'send you to http://www.cplusplus.com/doc/tutorial/namespaces/#scopes once again

kshegunov

@VRonin said in Picture:

I'm surprised your compiler doesn't yell about redefinition

Not redefinition, shadowing, hence no yelling. :)

VRonin

@kshegunov said in Picture:

shadowing

The case @kshegunov is explaining is in the 3rd code block of the link above:

// inner block scopes
#include <iostream>
using namespace std;

int main () {
  int x = 10;
  int y = 20;
  {
    int x;   // ok, inner scope.
    x = 50;  // sets value to inner x
    y = 50;  // sets value to (outer) y
    cout << "inner block:\n";
    cout << "x: " << x << '\n';
    cout << "y: " << y << '\n';
  }
  cout << "outer block:\n";
  cout << "x: " << x << '\n';
  cout << "y: " << y << '\n';
  return 0;
}

This means I should go back to that tutorial myself

Payx

@VRonin so if i want use my picture in an other function i have to declare it before my function as i did for

QColor dominantColor(const QImage& image, const QPoint& topLeft, const QSize& rectSize);

so i have to add a line code QImage pixi in my .cpp ?

why not in my .h, and why

QColor dominantColor

dont work in my .h too ?