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MouseAction


Unit:SDL_dendrogram
Class:TDendrogram
Declaration:property MouseAction: TMouseActMode;

The property MouseAction facilitates interactive zooming and panning of the dendrogram. This property may take the following possible values.

maDragCrossH Drag the crosshair using the mouse.
maNone No built-in interaction is possible. The only way to apply a mouse controlled action is by utilizing the mouse events.
maPan The data display can be panned by pressing and holding the left mouse button. The data image will then follow the mouse movement. Please note that maPan is only effective in the area of the drawn dendrogram. The panning mode in the neighboring areas (scale and object labels) is different to enable panning of the dendrogram in parallel to the axes.
maPanHoriz The data display can be panned only horizontally by pressing and holding the left mouse button.
maPanVert The data display can be panned only vertically by pressing and holding the left mouse button.
maZoomDrag This mode enables the user both to increase and to decrease the magnification factor of the graph. The left mouse button has to be pressed and held down. The magnification of the data image will then follow the mouse movement. Moving to the bottom zooms out of the data; moving to the top zooms into the data.
maZoomWind The user can zoom into a rectangular region of the data display. Therefore he has to press and hold down the left mouse button at one of the corners of the intended region. Thereafter a rectangle follows the mouse cursor indicating the region to be zoomed. Releasing the left button selects this region and zooms into the data by displaying exactly this region.

Hint 1: These interactive modes will function smoothly only on a powerful computer with a proper graphics card.

Hint 2: In the case of type ambiguities concerning maNone please visit the SDL TechnNotes.

Example: This property is used in the following example program (see http://www.lohninger.com/examples.html for downloading the code): dendro



Last Update: 2016-Feb-23