# How to reverse the direction of the y axes on Graphics

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 3 '14 at 6:40
• I don't understand what he do in his answer. – tower120 Apr 3 '14 at 11:16

## 1 Answer

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}]] &}] • What is #, ##, &@ ? :) – tower120 Apr 3 '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 3 '14 at 17:29
• and how do I know the maximum "y" value of my drawings? – tower120 Apr 4 '14 at 3:36
• What is MMA? What a function of two arguments? – tower120 Apr 4 '14 at 7:20
• @Michael Good point. – Kuba Apr 22 '15 at 6:36