Examples: DPI: Portable DPI related helpers in the _Win32 examples. Using one in examples's main.cpp, the GetDpiScale functions are not wired anywhere for now. (#1542, #1676)

Viewport: Fix dropping back viewport not being moved to the front of the window list. (Now that viewport are more tighly coupled to a single root window) (#1542)

Viewport, DPI: Don't activate current window until a viewport has been selected. At this point we'll have the proper size/scale for the current DPI + fix viewport callback when appending to an existing window more than once a frame. (#1542, #1676)

Viewport, DPI: Select viewport before locking style sizes and before handling double-click-on-title-bar to collapse. (#1542, #1676)

Merge branch 'master' into viewport

Viewport,Platform: Added GetWindowDpiScale() platform interface, changes of scale are reflected by positioning and resizing windows in their given viewport. (#1542)

Updated Changelog following merge of #1619 + fixed entry added to wrong version Changelog in 1ef1acb

Viewport: Coupling non-main viewport to one window. Viewport name derived from the window. Added ImGuiConfigFlags_PlatformNoTaskBar, off by default (aka re-established task-bars by default for now). (#1542)

Merge branch 'master' into font_offset

Comments, Changelog

Viewport: Disable extra viewports from hosting other windows. (#1542)

Fixed warnings.

Viewport: Reorganized viewport enable flags. Both user + platform + renderer need to enable a flag. (#1542)

Viewport: Modal display their darkneing/whitening layer over all viewports. (#1542)

Viewport: Various sanity fixes. Popup always inherit viewport from their parent for now. (#1542)

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_glfw.h
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.h
#	imgui.cpp

Render: Removed the code that disable render if style.Alpha is 0.0f, it is both incorrect (as style Alpha can be modified mid-frame), not really necessary (just tested that full Alpha = 0 will lead to empty draw lists!) and misleading (bulk of the work was already done).

Viewport: Tracking current viewport we are appending to + added callback in PlatformInterface for DPI purpose (WIP). (#1542)

Fixed type cast warning.

Comments, FAQ update.

Columns: Fixed destructive small resize. (#1656). The OffsetNorm clamp introduced by #913 was ok as it didn't write back into the storage, which #1499 started doing making it destructive. Right now I don't think the clamp is needed at all. It had uses (eg: hide the issue fixed by bf7481e).

Columns: Extent stop at the right-most clipped pixel. The right-most column might appear a little wider but it's usable space matches the others. (#125). +9 Internal: Store InnerClipRect.

Columns: Clamping MaxX above MinX. This shouldn't have much of a benefit / affect, but the internal values are more sane this way. (#125)

Columns: Adding per-window display in Metrics. Tidying up, removing old code/comments. (#125, #1499, #1656)

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/allegro5_example/main.cpp
#	examples/directx10_example/main.cpp
#	examples/directx11_example/main.cpp
#	examples/directx12_example/main.cpp
#	examples/directx9_example/main.cpp
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_glfw.h
#	examples/imgui_impl_vulkan.cpp
#	examples/opengl2_example/imgui_impl_glfw_gl2.cpp
#	examples/opengl2_example/main.cpp
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/opengl3_example/main.cpp
#	examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp
#	examples/sdl_opengl2_example/main.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp
#	examples/sdl_opengl3_example/main.cpp
#	examples/vulkan_example/main.cpp
#	imgui.cpp
#	imgui.h

Viewport: Give a chance to platform and renderer to actually destroy their data. Otherwise the regular ImplXXX_Shutdown + following by DestroyContext() order fails to fullifl this. (#1542)

Renamed ImGuiStyleVar_Count_ to ImGuiStyleVar_COUNT for consistency with other enums. Added

Added ArrowButton(). Exposed ImGuiDir.

BeginCombo(): Added ImGuiComboFlags_NoArrowButton and ImGuiComboFlags_NoPreview flags + hover color matches drag and sliders.

Merge branch 'patch-1' of https://github.com/stfx/imgui into stfx-patch-1