Fix division by 0 in ImGui::PlotLines when values_count = 1

[Lectem]

If values_count == 1, then there is a division by zero in const float t_step = 1.0f / (float)res_w; as res_w can be 0 ( ImMin((int)graph_size.x, values_count) + ((plot_type == ImGuiPlotType_Lines) ? -1 : 0) == 1 - 1 == 0 )

This can be reproduced with the following snippet:

float values[1] = {0.f};
ImGui::PlotLines("Boom", values, 1);

[Lectem]

Fixed by 5e3a1de

[ocornut]

Thank you, fixed!
(I have fixed this with another patch now, since yours doesn't follow the coding guidelines of imgui)

I don't think the division by zero here was harmful in this context, does your compile/cpu setting actually break on division by zero?

[Lectem]

I don't think the division by zero here was harmful in this context, does your compile/cpu setting actually break on division by zero?

Yes we have float exceptions enabled in our application!

[Lectem]

since yours doesn't follow the coding guidelines of imgui

Just to know for the future, was the issue constructing the int from bool ("cast") ?
Thanks for the quick response by the way.

[ocornut]

• We use C-style cast only.
• Extra space between the two parenthesis
• In this particular case, I feel that casting the bool resulting from a == into an integer and using it in an integer compare (which is not != 0) is a little obtuse, and best done via a temporary variable.

Thanks for asking!