From d83c0090b12536ee6076c4239bf28f9ce7f2134e Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Wed, 23 Feb 2022 11:34:25 +0000
Subject: [PATCH] Renderables

---
 sandbox/uber.css                    |  4 +++
 sandbox/uber.py                     | 18 +++++++++++++
 src/textual/geometry.py             |  9 +++++++
 src/textual/renderables/blank.py    | 28 +++++++++++++++++++++
 src/textual/renderables/gradient.py | 39 +++++++++++++++++++++++++++++
 5 files changed, 98 insertions(+)
 create mode 100644 sandbox/uber.css
 create mode 100644 sandbox/uber.py
 create mode 100644 src/textual/renderables/blank.py
 create mode 100644 src/textual/renderables/gradient.py

diff --git a/sandbox/uber.css b/sandbox/uber.css
new file mode 100644
index 000000000..960f4b47b
--- /dev/null
+++ b/sandbox/uber.css
@@ -0,0 +1,4 @@
+#uber {
+  border: heavy green;
+  margin: 5;
+}
diff --git a/sandbox/uber.py b/sandbox/uber.py
new file mode 100644
index 000000000..472f4c20e
--- /dev/null
+++ b/sandbox/uber.py
@@ -0,0 +1,18 @@
+from textual.app import App
+from textual import events
+from textual.widgets import Placeholder
+from textual.widget import Widget
+
+
+class BasicApp(App):
+    """Sandbox application used for testing/development by Textual developers"""
+
+    def on_mount(self):
+        """Build layout here."""
+        self.mount(uber=Widget())
+
+    async def on_key(self, event: events.Key) -> None:
+        await self.dispatch_key(event)
+
+
+BasicApp.run(css_file="uber.css", log="textual.log")
diff --git a/src/textual/geometry.py b/src/textual/geometry.py
index cf07808f4..922084c44 100644
--- a/src/textual/geometry.py
+++ b/src/textual/geometry.py
@@ -1,3 +1,10 @@
+"""
+
+Functions and classes to manage terminal geometry (anything involving coordinates or dimensions).
+
+"""
+
+
 from __future__ import annotations
 
 from math import sqrt
@@ -209,6 +216,7 @@ class Region(NamedTuple):
         return cls(x, y, width, height)
 
     def __bool__(self) -> bool:
+        """A Region is considered False when it has no area."""
         return bool(self.width and self.height)
 
     @property
@@ -509,6 +517,7 @@ class Spacing(NamedTuple):
 
     @property
     def css(self) -> str:
+        """Gets a string containing the spacing in CSS format."""
         top, right, bottom, left = self
         if top == right == bottom == left:
             return f"{top}"
diff --git a/src/textual/renderables/blank.py b/src/textual/renderables/blank.py
new file mode 100644
index 000000000..50c949283
--- /dev/null
+++ b/src/textual/renderables/blank.py
@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from rich.console import ConsoleOptions, Console, RenderResult
+from rich.color import Color
+from rich.segment import Segment
+from rich.style import Style
+
+
+class Blank:
+    """Draw solid background color."""
+
+    def __init__(self, color: str) -> None:
+        self._style = Style.from_color(None, Color.parse(color))
+
+    def __rich_console__(
+        self, console: Console, options: ConsoleOptions
+    ) -> RenderResult:
+        width = options.max_width
+        height = options.height or options.max_height
+
+        segment = Segment(f"{' ' * width}\n", self._style)
+        yield from [segment] * height
+
+
+if __name__ == "__main__":
+    from rich import print
+
+    print(Blank("red"))
diff --git a/src/textual/renderables/gradient.py b/src/textual/renderables/gradient.py
new file mode 100644
index 000000000..c7eb1a53f
--- /dev/null
+++ b/src/textual/renderables/gradient.py
@@ -0,0 +1,39 @@
+from __future__ import annotations
+
+from rich.console import ConsoleOptions, Console, RenderResult
+from rich.color import Color
+from rich.segment import Segment
+from rich.style import Style
+
+from ._blend_colors import blend_colors_rgb
+
+
+class VerticalGradient:
+    """Draw a vertical gradient."""
+
+    def __init__(self, color1: str, color2: str) -> None:
+        self._color1 = Color.parse(color1).get_truecolor()
+        self._color2 = Color.parse(color2).get_truecolor()
+
+    def __rich_console__(
+        self, console: Console, options: ConsoleOptions
+    ) -> RenderResult:
+        width = options.max_width
+        height = options.height or options.max_height
+        color1 = self._color1
+        color2 = self._color2
+        default_color = Color.default()
+        from_color = Style.from_color
+        for y in range(height):
+            yield Segment(
+                f"{width * ' '}\n",
+                from_color(
+                    default_color, blend_colors_rgb(color1, color2, y / (height - 1))
+                ),
+            )
+
+
+if __name__ == "__main__":
+    from rich import print
+
+    print(VerticalGradient("red", "blue"))