How to reverse the direction of the y axes on Graphics

Question

Question related to this one, except I need the same for the Graphics.

Lets say I have the following drawings:

Graphics[{  
  Line[{ Q, P, V }] ,
  Arrow[{P, P + v }] ,
  Arrow[{P, P + vx }] ,
  Arrow[{P, P + vy}] ,

  {Dashed, 
   Line[{Q + (dir1*d1), P + v,  V + (dir2*d2)}]
   },

  FontSize -> 16, Background -> RGBColor[1, 1, 1, 1],
  Text["Q", Q],
  Text["P", P],
  Text["V", V],
  }, Axes -> True]

But on my drawing sysytem (this drawing should illustrate part of it work), the screen coordinates goes from top to bottom (in reverse order). So I want to reverse it somehow.

Rasher's answer in the question you linked to is probably the way to go. — C. E., Apr 03 '14 at 06:40

Kuba · Accepted Answer · 2014-04-03T13:00:22.587

1

Rasher's code will be usefull here but we also have to Scale all the obcjets which is easy but no so simple as - in case of Plot.

Graphics[
 Scale[#, {1, -1}, {0, 0}] &@{Circle[{2, 2}], Arrow[{{3, 2}, {5, 3}}]}
 ,
 Axes -> True, AxesOrigin -> {0, 0}, BaseStyle -> {15, Bold}, 
 AxesStyle -> {Arrowheads@.05, Arrowheads[{-.05, 0}]}, 
 Ticks -> {Automatic, 
           With[{set = N@FindDivisions[{##}, 25]}, 
                Table[If[ Mod[i, 5] == 2, 
                         {set[[i]], -set[[i]], {.02, 0}},
                         {set[[i]], "", {.01, 0}}], {i, Length@set}]] &}]

enter image description here

edited Apr 03 '14 at 13:00

answered Apr 03 '14 at 12:21

Kuba

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What is #, ##, &@ ? :) – tower120 Apr 03 '14 at 17:00
Is it possible to do something with number 25 here {set = N@FindDivisions[{##}, 25]}? Which, I belive, you just pick. – tower120 Apr 03 '14 at 17:29
and how do I know the maximum "y" value of my drawings? – tower120 Apr 04 '14 at 03:36
What is MMA? What a function of two arguments? – tower120 Apr 04 '14 at 07:20
I read it, your function provide pairs [value, label]. Am I right? But how it knows, that we need 25 ticks, not 30 , not 40 (which makes each tick samller)? – tower120 Apr 04 '14 at 07:33
But why 25?????? 25 means - we want 25 ticks for ALL drawing height. Am I right? This means, tick lenght is height/25. What am I missing? – tower120 Apr 04 '14 at 07:40
Unfortunately, Scale[] inverts all Text elements, so now they are upside down. – Michael Apr 19 '15 at 19:40
1

@Michael Good point. – Kuba Apr 22 '15 at 06:36

How to reverse the direction of the y axes on Graphics

1 Answers1

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