Drawing Door Frames

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Problem Description

An exercise to draw doors subdivided with  one or more vertical frames separated and divided by mullions of a given size.

Background & Techniques

This program was the result of a request from a Delphi programmer who was faced with this problem in the course of developing a piece of software for their business.   It was a mildly challenging exercise just to prove that it still could be done by this 77 year old programmer.    Haven't lost it yet!

The five Input values are:  1) Door Width, 2) Door Height, 3) Number of frames in the door, 4) Width of Mullions, and 5) Height  above door bottom to the top of cross-mullion within each frame.   

Non-programmers are welcome to read on, but may want to jump to bottom of this page to download the executable program now.

Programmer's Notes:

"Rectangle" was the only TCanvas method used in drawing a door. The problems included:

  • Calculating frame width: FrameWidth = DoorWidth - MullionWidth x (NbrFrames + 1)) / Number of Panels.
  • Calculating frame Left/Top corner Nth frame (L, T).  L=MullionWidth + (N-1) x (FrameWiidth --MullionWindth); T = Dootop + MullionWidth   
  • Calculating frame rectangle relative to passed (L,T) value:
    •  Lower panel Top/Left corner (PL,Pt):  PL= L;  PT = Doorheight - MullionHeightAboveBase + MullionWidth.
    • Lower panel Height frames: Panelheight = MullionHeightAboveBase - 2 x MullionWidth.
    • Top/Left corner of the top panel within frames (PL,PT):  PL = L; PT = T.  
    • Height of the top panel within frames:  PanelHeight = Doorheight - MullionHeightAboveBase.
  • Scaling the calculated values to display centered in the TImage canvas:   Converting from millimeters (or any other unit) to pixels requires multiplying by a pixels/unit scaling factor.   Here we'll calculate two candidates; one for width and one for height and take the smaller value as the one to use.  I chose to make the top left  corner of the door image at 10% from the left and from the top of the TImage  and occupy 80% of the height and /or width.  So ScaleX = 0.8 x Timage width / Doorwidth; ScaleY = 0.8 x TImage.Height / DoorHeight, and Scale = min(scalex, scaley).   Scaled  versions of the dimensional parameters described above are  used for drawing the rectangles. 

Running/Exploring the Program 

Suggestions for Further Explorations



Original:  March 18, 2016

Modified:  March 19, 2016

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