Boundaries of graphical objects not displayed correctly

Question

Bug introduced in 10.0.0 and fixed in 10.0.1

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I have encountered two situations where Mathematica 10 is mishandling the outer pixels of plainly simple objects.

I input this:

Rasterize[Graphics[{}, Background -> Black, ImageSize -> {19, 19}]]

It should basically create a 19x19 pixel black square, but instead I get this:

If you select the image you will see an extra white pixel row on the top. Indeed, this is because the ImageDimensions[%] gives {19, 20}. A similar problem occurs with some other pixel sizes.

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A similar effect takes place in barlegends:

GraphicsRow[{BarLegend[{"DeepSeaColors", {0, 1}}], BarLegend[{"DeepSeaColors", {0, 1}}, 
  LegendLayout -> "ReversedColumn"]}]

These are two bar legends going from 0 to 1, but the second one is reversed. The images look like this:

Here, the regular bar legend is okay, but the reversed one misses a thin grey line on one side.

Questions: Is it a bug? Does is happen only on my machine (Ubuntu 14)? Is it fixable (especially for the Legends)?

Answer 1

I was able to isolate the problem with BarLegend in v.10.0.0. Yes, it is clearly a bug.

Let us see the how the thin grey lines are implemented:

Cases[
 ToBoxes[BarLegend[{"DeepSeaColors", {0, 1}}, 
   LegendLayout -> "ReversedColumn"]], _LineBox, Infinity]

{LineBox[
  NCache[{{-(15/2), 225/2}, {15/2, 225/2}, {15/
     2, -(225/2)}, {-(15/2), -(225/2)}}, {{-7.5, 112.5}, {7.5, 
     112.5}, {7.5, -112.5}, {-7.5, -112.5}}]], 
 LineBox[{{7.5, 112.5}, {7.5, -112.5}}], 
 LineBox[{{{7.5, 112.5}, Offset[{4., 0}, {7.5, 112.5}]}, {{7.5, 67.5},
     Offset[{4., 0}, {7.5, 67.5}]}, {{7.5, 22.5}, 
    Offset[{4., 0}, {7.5, 22.5}]}, {{7.5, -22.5}, 
    Offset[{4., 0}, {7.5, -22.5}]}, {{7.5, -67.5}, 
    Offset[{4., 0}, {7.5, -67.5}]}, {{7.5, -112.5}, 
    Offset[{4., 0}, {7.5, -112.5}]}}], 
 LineBox[{{{7.5, 101.25}, 
    Offset[{2.5, 0.}, {7.5, 101.25}]}, {{7.5, 90.}, 
    Offset[{2.5, 0.}, {7.5, 90.}]}, {{7.5, 78.75}, 
    Offset[{2.5, 0.}, {7.5, 78.75}]}, {{7.5, 56.25}, 
    Offset[{2.5, 0.}, {7.5, 56.25}]}, {{7.5, 45.}, 
    Offset[{2.5, 0.}, {7.5, 45.}]}, {{7.5, 33.75}, 
    Offset[{2.5, 0.}, {7.5, 33.75}]}, {{7.5, 11.25}, 
    Offset[{2.5, 0.}, {7.5, 11.25}]}, {{7.5, 0.}, 
    Offset[{2.5, 0.}, {7.5, 0.}]}, {{7.5, -11.25}, 
    Offset[{2.5, 0.}, {7.5, -11.25}]}, {{7.5, -33.75}, 
    Offset[{2.5, 0.}, {7.5, -33.75}]}, {{7.5, -45.}, 
    Offset[{2.5, 0.}, {7.5, -45.}]}, {{7.5, -56.25}, 
    Offset[{2.5, 0.}, {7.5, -56.25}]}, {{7.5, -78.75}, 
    Offset[{2.5, 0.}, {7.5, -78.75}]}, {{7.5, -90.}, 
    Offset[{2.5, 0.}, {7.5, -90.}]}, {{7.5, -101.25}, 
    Offset[{2.5, 0.}, {7.5, -101.25}]}}]}

Let us visualize them:

Graphics[%]

We see that the left line is simply absent. Why? Because the second line LineBox[{{7.5, 112.5}, {7.5, -112.5}}] should have negative X coordinates in order to be placed on the left:

Graphics[{Line[NCache[{{-(15/2), 225/2}, {15/2, 225/2}, {15/2, -(225/2)}, {-(15/2), -(225/2)}}, {{-7.5, 112.5}, {7.5, 112.5}, {7.5, -112.5}, {-7.5, -112.5}}]], 
Line[{{-7.5, 112.5}, {-7.5, -112.5}}]}]

So the source of the problem is now clear: the developer just forgot to change the sign of the coordinates of this line when implemented LegendLayout -> "ReversedColumn" on the basis of already implemented LegendLayout -> "Column".