Why is my rasterized graphic blank?

Question

Bug introduced in 7.0 or earlier, and persisting through 10.1 or later (OSX 10.10.2)

Consider the following code:

jet[u_?NumericQ] := 
  Blend[{{0, RGBColor[0, 0, 9/16]}, {1/9, Blue}, {23/63, 
      Cyan}, {13/21, Yellow}, {47/63, Orange}, {55/63, Red}, {1, 
      RGBColor[1/2, 0, 0]}}, u] /; 0 <= u <= 1;
(* jet function get from http://stackoverflow.com/a/9321152/1363677*)
caxis[x_, {min_, max_}] := 
  If[x < min, jet[0], If[x > max, jet[1], jet[(x - min)/(max - min)]]];

data1 = Table[
   Sinc[x*y] + RandomReal[{0., 0.2}], {x, -2 Pi, 2 Pi, 0.05}, {y, -2 Pi, 2 Pi, 0.05}];
data2 = Table[
   Sinc[x*y] + RandomReal[{0., 0.2}], {x, -2 Pi, 2 Pi, 0.02}, {y, -2 Pi, 2 Pi, 0.02}];

Row[{Graphics[Raster[data1, ColorFunction -> (caxis[#, {-0.5, 2}] &)],
    ImageSize -> 200],
  Graphics[Raster[data2, ColorFunction -> (caxis[#, {-0.5, 2}] &)], 
   ImageSize -> 200],
  Graphics[Raster[data2, ColorFunction -> "BlueGreenYellow"], 
   ImageSize -> 200]}]

It gives the output:

enter image description here

Why is the second plot blank?

If the dynamic updating is turned off, all of the three are blank.

enter image description here

Why does Mathematica behave like this? I'm using OSX 10.8.4 on a Macbook Air with 1.7 GHz Intel Core i5 and 4GB memory.

You should certainly indicate what version and OS you're working with for this type of question. The code works fine for me in version 9.0.0 on Mac OSX 10.7.4. — Mark McClure, Jun 20 '13 at 17:21
@Silvia did you monitor the setting "Dynamic Updating Enabled" in the "Evaluation" menu? — xslittlegrass, Jun 20 '13 at 17:49
It still presents blank graphics when I disable the Dynamic Updating. The best I can tell is that your ColorFunction in the output Cell, which is ColorFunction->($CellContext`caxis[#, {-0.5, 2}]& ), needs Dynamic Updating enabled to function. — Silvia, Jun 20 '13 at 17:55
Yes I confirmed that. See my last comment please. btw with Dynamic Updating enabled, the first time I found the 2nd plot is blank, but then I can't reproduce that. — Silvia, Jun 20 '13 at 17:56
MMA8 with OSX 10.6.8 does not exhibit this behavior. All plots displayed with dynamic updating on or off. — Christina, Jun 20 '13 at 19:38
MMA8 with Windows XP does not display middle plot when dynamic updating is on. When dynamic updating is off, nothind is displayed. — Christina, Jun 20 '13 at 19:43
this is the issue with what was originally my wavelet scalogram exporting — amr, Jun 20 '13 at 20:11
Identical behavior observed here on 7.0.1, 8.0.4, and 9.0.1, on Windows 2003 x64. Middle plot is missing in all cases. — Oleksandr R., Jun 22 '13 at 02:34
@Mr.Wizard I have tested on 10.0.1, and now I'm install a 10.0.2 and will test that and update the post. — xslittlegrass, Feb 12 '15 at 19:28
@Mr.Wizard version 10 cannot be installed on Windows 2003. On Windows 7, 10.0.1 does not exhibit the bug. I didn't install 10.0.2 yet. — Oleksandr R., Feb 13 '15 at 16:11
@Oleksandr Thank you. I forgot about end-of-support with old Windows editions. (A part of me has trouble calling 2003 old -- is it really 2015 already!?) — Mr.Wizard, Feb 13 '15 at 18:42

george2079 · Accepted Answer · 2013-06-20T20:16:31.070

8

Label this a most bizarre bug -- I can reproduce the problem (v9.0.0.0) -- the fix, change all those integer fractions in Blend to decimals..

This fails:

jet[u_?NumericQ] :=  Blend[{{0, RGBColor[0, 0, 1/9]}, {1, Red}}, u] /; 0 <= u <= 1

This works

jet[u_?NumericQ] := Blend[{{0, RGBColor[0, 0, 0.11111111]}, {1, Red}}, u] /; 0 <= u <= 1

Edit: another curiosity.. this should be the same (I think..) normalising the values before passing to the color function.

Graphics[Raster[data1, Automatic, {-.05, 2}, 
         ColorFunction -> (caxis[#, {0, 1}] &)], ImageSize -> 200]

Although it works, the colors are substantially different.

edited Jun 20 '13 at 20:16

answered Jun 20 '13 at 18:13

george2079

38,913
1
43
110

neither works with dynamic updating off. – george2079 Jun 20 '13 at 18:15
1

I agree this is a bug (+1). It also disappears when I remove the RandomReal from the definition of the data. – Jens Jun 20 '13 at 18:22

Why is my rasterized graphic blank?

1 Answers1

Linked