Rubber Band crecttracker usage experience

The crecttracker is called a "rubber band". It is the basis for further operations by selecting an object in the window editing. There are two ways to use rubber bands: 1. Hand-written rubber bands, which are well controlled in the program. 2. Use the crecttracker system class. Here I will introduce the use of crecttracker. For detailed parameters and usage of crecttracker, refer to csdn. I mainly introduce the usage of basic programs.

First, create a new member variable in the xxxview class:

CRectTracker m_tracker;

Second, set the attribute of the rubber band in the constructor of the xxxview class.

m_tracker.m_nStyle =CRectTracker::resizeInside|CRectTracker::dottedLine;  m_tracker.m_rect = CRect(-1, -1, -1, -1);

M_nstyle is the rubber band type. The specific types include:

Crecttracker: solidlineUse a solid line for the rectangle border.

Crecttracker: dottedlineUse a dotted line for the rectangle border.

Crecttracker: hatchedborderUse a hatched pattern for the rectangle border.

Crecttracker: resizeinsideResize handles located inside the rectangle.

Crecttracker: resizeoutsideResize handles located outside the rectangle.

Crecttracker: hatchinsideHatched pattern covers the entire rectangle.

M_rect sets the size of the initial rubber band (rectangle). Because I need to select an object based on the mouse in the program, the initial value is (-1,-1,-1,-1) invisible.

After the initial work last night, to get a rubber band in the program, you just need to respond to the left-click event onlbuttondown (uint nflags, cpoint point ). The Code is as follows:

// For this code, refer to int nin = m_tracker.hittest (point) written by a high-end user. // you can find out where the IF (nin <0) is located. // It is not in the quadrilateral area; {m_tracker.m_rect.setrectempty (); invalidate ();} else // In the quadrilateral area: {cclientdc DC (this); m_tracker.draw (& DC); m_tracker.track (this, point, true ); // track () is the most attractive function in crecttracker. It always changes the caller's m_rect; onpreparedc (& DC); cpoint pt_end; // The following Code considers scrollview and records the logical location of coordinates getcursorpos (& pt_end); rect. right = pt_end.x; rect. bottom = pt_end.y; screentoclient (& rect); pt_end.x = rect. right; pt_end.y = rect. bottom; If (pt_end! = M_pt) // manually call lbuttonup; in fact, you can also complete the rubber band movement without calling. However, my program needs to continue to process sendmessage (wm_lbuttonup); invalidate ();}

In response to the wm_lbuttonup mouse release event, you can add the code you want to process. In this way, the crecttracker class can be fully used.

 

 

We recommend a more detailed example here.

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