Fix bug of GL ERROR when window is minimized

[maxint]

Add more information.

In GLFW implementation, glfwGetWindowSize(g_Window, &w, &h) and glfwGetFramebufferSize(g_Window, &display_w, &display_h) return zero width and height when render window is minimized. Then glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height) reports GL_ERROR when zero parameters.

Thanks for this tiny, handful and great open source project!

[ocornut]

Thanks. I'll reapply this manually as the PR seems to have unrelated changes (imgui_internal, spacing).

if (fb_width == 0 && fb_height == 0)
        return;

Should perhaps be:

if (fb_width == 0 || fb_height == 0)
     return;

and

io.DisplayFramebufferScale = ImVec2((float)display_w / ImMax(1, w), (float)display_h / ImMax(1, h));

should be

io.DisplayFramebufferScale = ImVec2(w ? ((float)display_w / w) : 0, h ? ((float)display_h / h) : 0);

So as to not assign a resolution value into a scale value.

[maxint]

You are right, I have merge old and new changes into one commit.

[ocornut]

Applied manually now. Thanks!

[maxint]

It's my pleasure 😄

[ocornut]

@maxint Sorry when I manually applied that the other day I actually let the early-return happen at the wrong spot and it caused problems (which your PR didn't have). It is fixed now.

[maxint]

@ocornut Got it. Thanks for your information.