Interactive moving of a region.

::drag_region1 is used to move a region on the display by mouse. Calling ::drag_region1 turns the region visible as soon as the left mouse button is pressed. Therefore the region's edges are displayed only. As representation mode the mode 'not' (see ::set_draw) is used during procedure's permanence. During the movement the cursor resides in the region's barycenter. If you move the mouse with pressed left mouse button, the depicted region follows - delayed - this movement. If you press the right mouse button you terminate ::drag_region1. The depicted region disappears from the display. Output is a region which corresponds to the last position on the display. You may pass even several regions at once. Procedure ::affine_trans_image moves the gray values.

Gray values of regions are not moved. With moving the input region it is not sure whether the gray values of the output regions are filled reasonable. This may occur if the gray values of the input regions do not comprise the whole image.

draw_region(&Obj,WindowHandle) ;
drag_region1(Obj,&New,WindowHandle) ;
disp_region(New,WindowHandle) ;
position(Obj,_,Row1,Column1,_,_,_,_) ;
position(New,_,Row2,Column2,_,_,_,_) ;
disp_arrow(WindowHandle,Row1,Column1,Row2,Column2,1.0) ;
fwrite_string("Transformation: ") ;
fwrite_string(Row2-Row1) ;
fwrite_string(", ") ;
fwrite_string(Column2-Column1) ;
fnew_line() ;

::drag_region1 returns H_MSG_TRUE, if a region is entered, the window is valid and the needed drawing mode (see ::set_insert) is available. If necessary, an exception handling is raised. You may determine the behavior after an empty input with ::set_system('no_object_result',<Result>).

::open_window

::reduce_domain, ::disp_region, ::set_colored, ::set_line_width, ::set_draw, ::set_insert

::get_mposition, ::move_region

::set_insert, ::set_draw, ::affine_trans_image

System