Styles renderer

src/textual/_styles_render.py

@@ -0,0 +1,196 @@
+from __future__ import annotations
+
+from rich.style import Style
+from typing import TYPE_CHECKING
+
+from rich.segment import Segment
+
+from ._border import get_box
+from .color import Color
+from ._segment_tools import line_crop
+from ._types import Lines
+from .geometry import Region, Size
+from .widget import Widget
+
+
+if TYPE_CHECKING:
+    from .css.styles import RenderStyles
+
+
+class StylesRenderer:
+    def __init__(self, widget: Widget) -> None:
+        self._widget = widget
+        self._cache: dict[int, list[Segment]] = {}
+        self._dirty_lines: set[int] = set()
+
+    def invalidate(self, region: Region) -> None:
+        self._dirty_lines.update(region.y_range)
+
+    def render(self, region: Region) -> Lines:
+
+        widget = self._widget
+        styles = widget.styles
+        size = widget.size
+        (base_background, base_color), (background, color) = widget.colors
+
+        return self._render(size, region, styles, base_background, background)
+
+    def _render(
+        self,
+        size: Size,
+        region: Region,
+        styles: RenderStyles,
+        base_background: Color,
+        background: Color,
+    ):
+        width, height = size
+        lines: Lines = []
+        add_line = lines.append
+
+        is_dirty = self._dirty_lines.__contains__
+        render_line = self.render_line
+        for y in region.y_range:
+            if is_dirty(y) or y not in self._cache:
+                line = render_line(styles, y, size, base_background, background)
+                self._cache[y] = line
+            else:
+                line = self._cache[y]
+            add_line(line)
+        self._dirty_lines.difference_update(region.y_range)
+
+        if region.x_extents != (0, width):
+            _line_crop = line_crop
+            x1, x2 = region.x_range
+            lines = [_line_crop(line, x1, x2, width) for line in lines]
+
+        return lines
+
+    def render_content_line(self, y: int, width: int) -> list[Segment]:
+        return [Segment((str(y) * width)[:width])]
+
+    def render_line(
+        self,
+        styles: RenderStyles,
+        y: int,
+        size: Size,
+        base_background: Color,
+        background: Color,
+    ) -> list[Segment]:
+
+        gutter = styles.gutter
+        width, height = size
+        content_width, content_height = size - gutter.totals
+        last_y = height - 1
+
+        pad_top, pad_right, pad_bottom, pad_left = styles.padding
+        (
+            (border_top, border_top_color),
+            (border_right, border_right_color),
+            (border_bottom, border_bottom_color),
+            (border_left, border_left_color),
+        ) = styles.border
+
+        inner_style = Style.from_color(base_background.rich_color)
+        outer_style = Style.from_color(background.rich_color)
+
+        if border_top and y in (0, last_y):
+
+            border_color = border_top_color if y == 0 else border_bottom_color
+            box_segments = get_box(
+                border_top if y == 0 else border_bottom,
+                inner_style,
+                outer_style,
+                Style.from_color(bgcolor=border_color.rich_color),
+            )
+            box1, box2, box3 = box_segments[0 if y == 0 else 2]
+
+            if border_left and border_right:
+                return [box1, Segment(box2.text * (width - 2), box2.style), box3]
+            elif border_left:
+                return [box1, Segment(box2.text * (width - 1), box2.style)]
+            return [Segment(box2.text * (width - 1), box2.style), box3]
+
+        if (pad_top and y < gutter.top) or (pad_bottom and y >= height - gutter.bottom):
+            background_style = Style.from_color(bgcolor=base_background.rich_color)
+            _, (left, _, _), _ = get_box(
+                border_left,
+                inner_style,
+                outer_style,
+                Style.from_color(bgcolor=border_left_color.rich_color),
+            )
+            _, (_, _, right), _ = get_box(
+                border_left,
+                inner_style,
+                outer_style,
+                Style.from_color(bgcolor=border_right_color.rich_color),
+            )
+            if border_left and border_right:
+                return [left, Segment(" " * (width - 2), background_style), right]
+            if border_left:
+                return [left, Segment(" " * (width - 1), background_style)]
+            if border_right:
+                return [Segment(" " * (width - 1), background_style), right]
+            return [Segment(" " * width, background_style)]
+
+        line_y = y - gutter.top
+        line = self.render_content_line(line_y, content_width)
+
+        if pad_left and pad_right:
+            line = [
+                Segment(" " * pad_left, inner_style),
+                *line,
+                Segment(" " * pad_right, inner_style),
+            ]
+        elif pad_left:
+            line = [
+                Segment(" " * pad_left, inner_style),
+                *line,
+            ]
+        elif pad_right:
+            line = [
+                *line,
+                Segment(" " * pad_right, inner_style),
+            ]
+
+        if not border_left and not border_right:
+            return line
+
+        _, (left, _, _), _ = get_box(
+            border_left,
+            inner_style,
+            outer_style,
+            Style.from_color(border_left_color.rich_color),
+        )
+        _, (_, _, right), _ = get_box(
+            border_left,
+            inner_style,
+            outer_style,
+            Style.from_color(border_right_color.rich_color),
+        )
+
+        if border_left and border_right:
+            return [left, *line, right]
+        elif border_left:
+            return [left, *line]
+
+        return [right, *line]
+
+
+if __name__ == "__main__":
+
+    from rich import print
+    from .css.styles import Styles
+
+    styles = Styles()
+    styles.padding = 2
+    styles.border = ("solid", Color.parse("red"))
+
+    size = Size(40, 10)
+    sr = StylesRenderer(None)
+    lines = sr._render(
+        size, size.region, styles, Color.parse("blue"), Color.parse("green")
+    )
+
+    from rich.segment import SegmentLines
+
+    print(SegmentLines(lines, new_lines=True))