Why does LineWidth not change when I set the LineWidth property of my plot?

Why is there no difference in the linewidth shown below?

subplot(2,1,1)

h1 = plot(1:10);

set(h1,'LineWidth',1.1)

subplot(2,1,2)

h2 = plot(1:10);

set(h1,'LineWidth',1.4)

Answer 1

[MathWorks Support Team]

This issue has to do with the fundamental resolution of your screen. Based on the description of the linewidth property:

 <http://www.mathworks.com/access/helpdesk/help/techdoc/ref/line_props.html>

Which says that 1 point = 1/72 inches. We also know that the ScreenPixelsPerInch which is a fundamental property of your screen can be found by performing a GET operation as follows:

get(0,'ScreenPixelsPerInch')

With this information you can obtain Pixels/Point [Dividing Pix/Inch by Points/Inch].

So for the change in Line Width to occur the number of Pixels/Point would need to be a whole pixel before change is noticed.

Illustrative Example:

close all

subplot(2,1,1)

h1 = plot(1:10);

set(h1,'LineWidth',1.1)

subplot(2,1,2)

h2 = plot(1:10);

Line_Width = 1.0;

for i = 1:100

      clc

      Pixels_Per_Point = (get(0,'ScreenPixelsPerInch')/72);

      subplot(2,1,2)

      set(h2,'LineWidth',Line_Width)

      Pixel_Width_Pts = Pixels_Per_Point*Line_Width

      Line_Width   = Line_Width + 0.1

      pause

end