Graphics

[TheDuncan]

I'm trying to do some basic graphics. Basically, I have an array of non-negative values that represent distance from a point and the array index represents the angle. I want to draw an oval at the origin and a circle at each of these places. I also need this area where I'm drawing this stuff to reside inside a section on a form and the rest of the form will have other text data.

Example:

If the ary[90] contains the value 5000 (distance is in millimeters) then it would draw a small circle straight ahead of the oval at the origin.

I have not done anything like this in Qt before so any resources, ideas, advice, etc is GREATLY appreciated.

Thanks.

[wysota]

Take a look at QPainter or QGraphicsView as any of the two approaches can be used in your situation.

[TheDuncan]

QPainter looks like what I need. I understand that it actually does the drawing, but what widgets can I use it on?

[wysota]

You can't use any widgets "on" it. It's a method of painting on widgets. You need to create a custom widget and draw it using QPainter in its paintEvent().

[TheDuncan]

Gotcha. How does this look for a start.

#ifndef MAPWIDGET_H
#define MAPWIDGET_H
 
#include <QWidget>
#include <QPainter>
 
class mapWidget : public QWidget
{
    Q_OBJECT
 
public:
    mapWidget(QWidget *parent = 0);
 
    void setLMS(long data[]);
    void setCamera(long data[]);
    void draw(QPainter *painter);
 
private:
    long lmsData[1080];
    long cameraData[180];
 
protected:
    void paintEvent(QPaintEvent * event);
 
};
 
#endif // MAPWIDGET_H

#ifndef MAPWIDGET_H
#define MAPWIDGET_H

#include <QWidget>
#include <QPainter>

class mapWidget : public QWidget
{
    Q_OBJECT

public:
    mapWidget(QWidget *parent = 0);
    
    void setLMS(long data[]);
    void setCamera(long data[]);
    void draw(QPainter *painter);

private:
    long lmsData[1080];
    long cameraData[180];

protected:
    void paintEvent(QPaintEvent * event);

};

#endif // MAPWIDGET_H

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[wysota]

Looks fine, just make the constructor explicit, "just in case". I'd also suggest to replace those C array arguments with QVector or QList.

[TheDuncan]

I'll do that.

How do you add a custom widget to a form?

[aamer4yu]

A custom widget is still a widget, you can directly show it using QWidget::show, or you can add it to any other widget in that widgets layout.
Give some time exploring the examples and documentation.

[TheDuncan]

Ok, but where do I use those commands? In main? Do How do I limit the space or assign where on the form the widget appears?

[TheDuncan]

Thanks for all the help. Works like a champ