GSoC Day 79

ZoomIn, ZoomOut, ResetZoom buttons

• Today the ZoomInButton, ZoomOutButton and ResetViewButton were added. It’s specifically ResetView because it may be used for the Panning functionality as well (which is the next thing to be worked on, along with a zoomSlider).
• We also spoke about Monoids and the conditions for a monoid. In CodeWorld, the & is the same as <>.

• For the drawing of the zoomInButton, this was the code for the image:

import CodeWorld

main :: IO ()
main = drawingOf magnifyingGlass 

magnifyingGlass = 
      translated (-0.05) (0.05) 
      (thickCircle 0.1 0.22  
      & solidRectangle 0.06 0.25
      & solidRectangle 0.25 0.06 
      & rotated (-pi / 4) (translated 0.35 0
      (solidRectangle 0.2 0.1)))

• Try it out here

• For the ResetViewButton, this was the code for the image:

import CodeWorld

main :: IO ()
main = drawingOf resetZoom

resetZoom = 
      colored white (solidRectangle 0.7 0.2) &
      colored white (solidRectangle 0.2 0.7) &
      thickRectangle 0.1 0.5 0.5 & 
      rectangle 0.8 0.8

• Try it out here

About formatting

• One of the things that has really astounded me this summer is how picky the senior engineers I’ve been working with are about code and formatting. I love it. Chris is particular about the code visually expressing its intent.

• For example

p =
        colored
            (RGBA 0 0 0 alpha)
            (translated (-0.05) (0.05) (
                thickCircle 0.1 0.22 <>
                solidRectangle 0.06 0.25 <>
                solidRectangle 0.25 0.06 <>
                rotated (-pi / 4)
                (translated 0.35 0 
                (solidRectangle 0.2 0.1))
            ))

• By viewing it, you immediately have the sense that there are outer functions and inner functions. So a function is applied to other nested values (sort of like you would imagine html would visually show which attributes are in which containers. I wish everyone would code like this!

• I think that that alone is motivation for me to keep going with programming. It’s almost like having good taste or finesse, which I guess would come with time and experience and a tonne of programming.

Anyways, that’s about it!