As `add_rect_filled_multicolor` does not have any option, the `build`
pattern is not used and calling `add_rect_filled_multicolor` directly
draws the rectangle on the window.
This patch uses bitflags to set the whether the corners are rounded.
Hence the `ImDrawCornerFlags` struct is defined, but only used
internally.
Externally, the valule of the flags can be changed with methods on the
`Rect` structure such as `round_top_right` or `round_bot_left`.
This patch wraps both ImDrawList_AddRectFilled and ImDrawList_AddRect.
ImDrawList_AddRectFilled is seen as a particular case of `add_rect`
where `filled` is set to `true`.
This patch makes the basic structure for a wrapper around Dear ImGui's
drawing API.
1. Implement `with_window_draw_list` method on Ui. Call this method to
get access to the `WindowDrawList` object. This object holds the methods
to access ImGui's drawing API.
2. Dear ImGui uses the ImU32 (an unsigned c_int) to represent colors in
the drawing API. This commit wraps this type with ImColor for
convenience. Any color representation (3or4-tuples, 3or4-arrays, ImU32
or ImVec4) can be converted into ImColor for convenience.
3. Difference between WindowDrawList and ChannelsSplit: Most drawing
functions can be called on WindowDrawList and ChannelsSplit objects.
However for safety, some functions can only be called on WindowDrawList
or ChannelsSplit instance. For example `channels_set_current` can only
be called after channels have been split. To avoid code duplication,
functions common to WindowDrawList and ChannelsSplit are implemented
within the `impl_draw_list_methods` macro.
4. Implement drawing functions (in this commit, add_line only). Calling
`add_line` returns a default representation of the line to be drawn, but
does not draw it. Then parameters, such as thickness, can be set. You
must call `build` to draw the line. All drawing functions will be
implemented following this pattern.
This reverts commit 0d10358942409cf8fad6fcb730dbedfbd7149df7.
`get_window_size` already exists and it's very easy to get just one
of the dimentions. As a result, delete get_window_width and
get_window_height.
If ImGui's mouse_draw_cursor is set to `true`, then ImGui draws the
cursor by itself, so this commits hids the OS cursor.
If ImGui's mouse_draw_cursor is set to `false`, then this commits
updates the OS cursor to the value set by the `set_mouse_cursor`
function provided by the ImGui instance.
For our use case, it seems safe to unwrap the result of the call to
glutin::Window::set_cursor_state, as an error can only potentially when
the `Grab` cursor state is used [1]. In ImGui's use case, the `Grab` state
is never used.
[1] https://docs.rs/crate/winit/0.11.2/source/src/platform/linux/x11/window.rs
Since the following pull request
https://github.com/tomaka/winit/pull/319, `winit` has deprecated
`get_inner_size_points()` and `get_inner_size_pixels()`.
We replace the deprecated API by `get_inner_size()` and
`hidpi_factor()`. The size in points in computed from the returned
hidpi_factor.
