Selection box on a picture

[Peterson]

Anyone have some code that will draw an expanding (or shrinking) rectangle on a form or picture, after I mousedown, move over a selected area, and then mouseup.

Mousemove fills in my rectangle for each increement in X and Y, and is too messy.

Using mousedown and moseup alone, I can draw the box at mouseup, but want to draw a rectangle according to the mouse movement after mousedown. I would also like the rectangle's lines to be dashed or even colored.

-lp

Hi.

Well, here is you code. This will allow you to draw a rectangle with a Click-and-drag method


Dim Clicked as Boolean
Dim first_corner_x as Single
Dim first_corner_y as Single
Dim last_pos_x as Single
Dim last_pos_y as single
Dim drawn as Boolean

Private Sub MouseDown_click(Index as integer, X as Single....)

Clicked = true 'Records the fact that the button is pressed
first_corner_x = X 'saves the x position of the cursor
first_corner_y = Y 'saves the y position of the cursor
drawn = false 'saves the fact that there is no rectangle drawn yet, so none to erase when the mouse will move
end sub

Private MouseMove_click(Index as integer,....)

If Clicked then 'verify the button is pressed

If drawn then
Line (first_corner_x,first_corner_y)-(last_pos_x,last_pos_y),,B 'erases the previous rectangle
end if

If X <> first_corner_x or Y <> first_corner_y then
Line (first_corner_x,first_corner_y)-(x,y),,B 'draws a new one
'save the new coordinates of the rectangle
'in order to erase it on the next mousemove
last_pos_x = X
last_pos_y = y
drawn = true 'saves the fact that a rectangle is now drawn and will need to be erased on the next mousemove
end if
End if
end sub

Private Sub MouseUp_click(Index as integer' X as Single....)

Clicked = False

end sub



The drawmode property set to XOR pen will allow the line to invert colors on every pixel which is not the background color. This way you can simply draw the same object over an exiting one to erase it without loosing the rest of the drawn elements.

That should do it.

Good luck!