From a40771f48f682286fa27999f3ee1fffdb9a27d8f Mon Sep 17 00:00:00 2001
From: Maic Siemering <maic@siemering.tech>
Date: Sun, 29 Sep 2024 21:26:05 +0200
Subject: [PATCH] feat(gui):support angle in UIImage

---
 arcade/gui/widgets/image.py | 56 +++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 9 deletions(-)

diff --git a/arcade/gui/widgets/image.py b/arcade/gui/widgets/image.py
index b234d9d57..44f7a0219 100644
--- a/arcade/gui/widgets/image.py
+++ b/arcade/gui/widgets/image.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import math
 from typing import Union
 
 from typing_extensions import override
@@ -28,6 +29,9 @@ class UIImage(UIWidget):
     alpha = Property(255)
     """Alpha value of the texture, value between 0 and 255.
     0 is fully transparent, 255 is fully visible."""
+    angle = Property(0)
+    """Angle of the texture in degrees.
+    The image will be rotated around its center and fitted into the widget size."""
 
     def __init__(
         self,
@@ -46,17 +50,51 @@ def __init__(
         )
         bind(self, "texture", self.trigger_render)
         bind(self, "alpha", self.trigger_full_render)
+        bind(self, "angle", self.trigger_full_render)
 
     @override
     def do_render(self, surface: Surface):
         """Render the stored texture in the size of the widget."""
-        self.prepare_render(surface)
         if self.texture:
-            surface.draw_texture(
-                x=0,
-                y=0,
-                width=self.content_width,
-                height=self.content_height,
-                tex=self.texture,
-                alpha=self.alpha,
-            )
+            self.prepare_render(surface)
+
+            if self.angle == 0:
+                surface.draw_texture(
+                    x=0,
+                    y=0,
+                    width=self.content_width,
+                    height=self.content_height,
+                    tex=self.texture,
+                    alpha=self.alpha,
+                )
+            else:
+                w = self.content_width
+                h = self.content_height
+                angle_radians = math.radians(self.angle)
+                cos_value = abs(math.cos(angle_radians))
+                sin_value = abs(math.sin(angle_radians))
+
+                # https://stackoverflow.com/a/33867165/2947505
+                # Calculate the minimum size of the rotated image
+                # W = w·|cos φ| + h·|sin φ|
+                w_rotated = w * cos_value + h * sin_value
+                # H = w·|sin φ| + h·|cos φ|
+                h_rotated = w * sin_value + h * cos_value
+                # a = min(wo / W, ho / H)
+                factor = min(w / w_rotated, h / h_rotated)
+                # W′ = a·w
+                w_fitted = factor * w
+                # H′ = a·h
+                h_fitted = factor * h
+
+                draw_rect = self.content_rect.align_left(0).align_bottom(0)
+                draw_rect = draw_rect.resize(w_fitted, h_fitted)
+                surface.draw_texture(
+                    x=draw_rect.left,
+                    y=draw_rect.bottom,
+                    width=draw_rect.width,
+                    height=draw_rect.height,
+                    tex=self.texture,
+                    alpha=self.alpha,
+                    angle=self.angle,
+                )