KtBrush
KtBrush is an abstract fill type with three concrete states - KtBrushNone, KtBrushSolid, KtBrushGradient - built on top of KtColor. Besides color, it carries the geometry needed to paint itself (rect, border radius/width, margin, rounded corners) and produces the actual GDI+ Brush, Pen, and GraphicsPath on demand.
Every example below builds a KtBrush through an implicit conversion, an operator, or a static factory - never new KtBrushSolid(...) / new KtBrushGradient(...) directly.
Creating a Brush
KtBrush solid = KtColor.PRIMARY; // implicit: KtColor -> solid brush (None if the color is empty)
KtBrush fromCss = Color.Red; // implicit: System.Drawing.Color -> solid brush
KtBrush gradient = (KtColor.Blue, KtColor.Sky); // implicit: 2-tuple -> gradient (start, stop)
KtBrush angled = (KtColor.Blue, KtColor.Sky, 45); // implicit: 3-tuple -> gradient with an angle
KtColor[] stops = [KtColor.Blue, KtColor.Sky, KtColor.Purple];
KtBrush fromArr = stops; // implicit: array -> first/last become start/stop
Ready-made semantic brushes and blank starting points:
KtBrush accent = KtBrush.PRIMARY; // PRIMARY -> SECONDARY gradient
KtBrush surface = KtBrush.BASE; // solid BASE
KtBrush blank = KtBrush.Solid; // an empty solid brush, ready to configure
KtBrush blankG = KtBrush.Gradient; // an empty gradient
From a string:
KtBrush byName = KtBrush.FromName("Solid"); // blank Solid / Gradient / None by kind name
KtBrush parsed1 = KtBrush.Parse("Blue"); // solid
KtBrush parsed2 = KtBrush.Parse("(Blue,Sky,45)"); // gradient with an angle
Kinds
bool isNone = someBrush.IsNone;
bool isSolid = someBrush.IsSolid;
bool isGradient = someBrush.IsGradient;
string kind = someBrush.Name; // "None" / "Solid" / "Gradient"
KtBrush copy = someBrush.Clone(); // same color(s)/angle, independent instance
Geometry & Border
The operators mutate the brush’s own rect/border state in place and return the same instance, so they chain naturally but don’t produce a copy:
var positioned = someBrush & new RectangleF(0, 0, 120, 40); // set the paint rectangle
var moved = someBrush & new PointF(10, 10); // reposition, keep size
var nudged = someBrush + new PointF(5, 0); // offset location by a delta
var back = someBrush - new PointF(5, 0);
var resized = someBrush & new SizeF(200, 60); // resize, keep location
var grown = someBrush + new SizeF(20, 0);
var shrunk = someBrush - new SizeF(20, 0); // clamped at 0
var inset = someBrush & new Padding(8); // shrinks/repositions the rect itself
someBrush.Margin(new Padding(8)); // a separate inset applied only when the Path is built
var rounded = someBrush & (radius: 12f, width: 2f); // border radius + width together
var placed = someBrush & (new RectangleF(0, 0, 120, 40), 12f); // rect + radius together
The same things are available as named, chainable methods if you’d rather not use operators: .Rect(rect), .Rect(rect, margin), .Margin(padding), .Border(radius, width, edges?), .BorderRadius(radius), .BorderWidth(width), .BorderEdges(corners).
A radius under 1 is treated as a fraction of the shape’s shorter side rather than a pixel value - the default, 0.5, produces a full pill/capsule. 1 or greater is an absolute pixel radius, clamped to half the shorter side.
Rounding can be limited to specific corners:
someBrush.BorderEdges(KtBrush.Corners.Top); // round only the top corners
someBrush.BorderEdges(new KtBrush.Edges { BottomLeft = false }); // per-corner toggle
var corners = KtBrush.CornerEdge(AnchorStyles.Top | AnchorStyles.Left); // map an anchor to matching Corners
var path = KtBrush.Squircle(rect, radius: 12f); // rounded-rect path, no brush instance needed
Gradient Angle
var rotated = someBrush % 90; // set a gradient's angle to 90°
var same = 90 % someBrush; // order doesn't matter
No-op (returns the brush unchanged) if it isn’t a gradient.
Content & Contrast
KtColor text = !someBrush; // readable text color for whatever's painted
KtColor text2 = ~someBrush; // same idea, from lightness only
KtColor onFill = someBrush % someColor; // flatten someColor onto the brush's own paint color
KtColor label = someBrush.Foreground(); // this brush's contrast color (same as !someBrush)
KtColor label2 = someBrush.Foreground(customFg); // customFg flattened onto that contrast color
For a gradient, !, ~, and brush % color currently all read only StartColor - StopColor isn’t factored in.
Combining & Fallback
KtBrush picked = hasOverride | fallbackBrush; // hasOverride if it's set, otherwise fallbackBrush
KtBrush replaced = hasOverride & otherBrush; // otherBrush if hasOverride is set, otherwise None
&/| also accept a KtColor directly on the right-hand side. Both also work with an Action for fluent side effects - the brush itself is always returned unchanged:
someBrush & (() => Invalidate()); // run the action only if the brush is set
someBrush | (() => LoadDefault()); // run the action only if the brush is None
Rendering
Brush gdiBrush = someBrush.Brush(); // System.Drawing.Brush, cached and reused
Pen gdiPen = someBrush.Pen(); // non-null only once a border width is set
GraphicsPath path = someBrush.Path(); // the rounded-rect/squircle outline
Color representative = someBrush; // implicit -> KtColor -> Color
string token = someBrush.Render(); // e.g. "Blue" or "(Blue,Sky,45)" - not the GDI+ Brush
Bitmap masked = someBrush.Render(sourceBitmap, borderRadius: 12f); // clips a bitmap to this brush's shape
someBrush.Dispose(KtBrush.KtGDIs.Brush); // force a specific cached resource (Pen/Brush/Path/All) to rebuild
State & Equality
if (someBrush) { } // implicit bool: true unless None
bool empty = someBrush.IsEmpty;
bool visible = someBrush.IsVisible;
bool same = brushA.Equals(brushB); // Solid/Gradient compare by color(s) + angle; the base falls back to reference equality
Interop
var json = new JObject { ["fill"] = someBrush }; // implicit -> JToken: [color] for solid, [start, stop] for gradient
Design-Time Support
A public KtBrush property gets PropertyGrid support automatically via KtBrushConverter - an expandable node with Color/StartColor/StopColor/Angle sub-properties depending on the current kind, plus correct serialization. No extra code required.