Note this PR should not be merged until after #600 is in.
I went on a rampage tonight. It all started with wanting to use more/better characters for frame and other UI elements like the round corners:
I decided I needed a character map app that would let me test which fonts had which Unicode sets in them.
As a result we have this PR
- Fixes `ScrollView` in several key ways:
- It now supports Computed layout and has constructors that don't require parameters.
- `ScrollBarViews` are now positioned using Computed layout versus error prone absoulte
- `ScrollBarViews` now correctly position themselves when one, either, or both are on/off.
- `IsVertical` is now a public property that does the expected thing when changed
- Mouse handling is better; there's still a bug where the mouse doesn't get grabbed by the `ScrollView` initially but I think this is a broader problem. I need @BDisp's help on this.
- The `Scrolling` Scenario was enhanced to demo dynamically adding/removing horizontal/vertical scrollbars (and to prove it was working right).
- I Enabled easy "infinite scroll capability" - CharMap literally lets you scroll over `int.MaxValue / 16` rows of data. Filling a `ContentView` with all of this and panning it around won't work. So I needed a way of having `Redraw` give me virtual coordinates. I did this by defining `OnDrawContent(Rect viewport)` and it's associated `event`:
```csharp
/// <summary>
/// Event invoked when the content area of the View is to be drawn.
/// </summary>
/// <remarks>
/// <para>
/// Will be invoked before any subviews added with <see cref="Add(View)"/> have been drawn.
/// </para>
/// <para>
/// Rect provides the view-relative rectangle describing the currently visible viewport into the <see cref="View"/>.
/// </para>
/// </remarks>
public event EventHandler<Rect> DrawContent;
/// <summary>
/// Enables overrides to draw infinitely scrolled content and/or a background behind added controls.
/// </summary>
/// <param name="viewport">The view-relative rectangle describing the currently visible viewport into the <see cref="View"/></param>
/// <remarks>
/// This method will be called before any subviews added with <see cref="Add(View)"/> have been drawn.
/// </remarks>
public virtual void OnDrawContent (Rect viewport)
{
DrawContent?.Invoke (this, viewport);
}
```
I originally just implemented this pattern in `ScrollView`. Then I realized I wanted the same thing out of ALL `Views`. Namely: the ability to do drawing on an event, particularly to be able to paint something in the background. So I added it to `View`.
Note, that these changes mean we are about 3 small steps away from moving the scollbars from `ScrollView` into ALL views. Which makes a lot of sense to me because I don't think we want to implement duplicative logic in, say `ListView` and `TextView` as well. Why not just do it once?
Along the way I fixed some other things:
- The `Checkbox.Toggled` event now passes state.
Here's some gifs.
Note:
- Scrollbars appear dynamically.
- Fast scrolling of huge data (using no memory).
- Static header
- Dynamic scrollbars on/off
- Note the bottom/right corner now draw correctly in all situations
This PR includes:
#586 - Fixed Clipping
#587 - LayoutComplete
#591 - Sys Console Scenario
#590 - Significantly improves MessageBox, Dialog, Frame drawning and more
See the PRs above for all the details.
Here are the issues this closes:
Closes#299 - MessageBox now auto sizes
Closes#557 - MessageBoxes on small screens
Closes#432 - MessageBox does not deal with long text; width/height params are goofy
Closes#521 - MessageBox should take ustrings (BREAKING CHANGE)
Closes#35 - Dialog should have 1 char padding around edges
Closes#570 - Dialog should use computed layout for buttons
Closes#470 - UI Catalog: Add Dialogs Scenario
Closes#569 - LayoutComplete event
Plus probably more.
+ Added Handled property of type bool to the KeyEventEventArgs class.
+ Added ability to stop further propagation for already handled events on Views for Keyboard related event subscribers (like KeyDown, KeyUp and KeyPress). The driver will check the Handled property of the KeyEventEventArgs passed to the subscribers and will stop any further invocations when its found true.
+ Updated Example project to expose the ability to programatically Open/Close a MenuBar from custom keystrokes.
This commit fixes an issue where the library would crash if the Subviews collection of the currently active View gets updated from inside any of the Keyboard event handlers, such as when the view is updated as a result of a custom Hotkey/Coldkey press.
