Size of rect property of widget (left, bottom, width, height) on macOS

[wkentaro]

The size information of rect property (e.g., Widget.rect.left) seems to be half of the actual.

This script runs without any problem on Linux https://gist.github.com/wkentaro/ff4b804df77d8292fdb7043c3e2489f9

but it looks like below on macOS:

If I change like below

diff --git a/spam.py b/spam.py
index a8e5067..4059f53 100644
--- a/spam.py
+++ b/spam.py
@@ -17,10 +17,10 @@ class SceneGroup(pyglet.graphics.Group):
         glPushAttrib(GL_ENABLE_BIT)
         glEnable(GL_SCISSOR_TEST)
         glScissor(
-            int(self.rect.left),
-            int(self.rect.bottom),
-            int(self.rect.width),
-            int(self.rect.height),
+            2 * int(self.rect.left),
+            2 * int(self.rect.bottom),
+            2 * int(self.rect.width),
+            2 * int(self.rect.height),
         )

         self._mode = (GLint)()
@@ -28,8 +28,8 @@ class SceneGroup(pyglet.graphics.Group):
         self._viewport = (GLint * 4)()
         glGetIntegerv(GL_VIEWPORT, self._viewport)

-        left, bottom = int(self.rect.left), int(self.rect.bottom)
-        width, height = int(self.rect.width), int(self.rect.height)
+        left, bottom = 2 * int(self.rect.left), 2 * int(self.rect.bottom)
+        width, height = 2 * int(self.rect.width), 2 * int(self.rect.height)
         glViewport(left, bottom, width, height)
         glMatrixMode(GL_PROJECTION)
         glPushMatrix()

It looks ok.

Is this an expected behavior? Should I always double the size of rect?

[kalekundert]

Looking at the two screenshots, the problem is that the MacOS window has twice as many pixels as it should have. Specifically, pyglet requests a window that is 1280 px wide, and glooey bases all of its calculations on that. But looking at the dimensions of the screenshots, the linux window is in fact 1280 px wide, while the MacOS window is 2554 px wide (2*1280=2560, I'm not sure why the window is 6 px narrower than that).

Does your Mac have a retina display, by any chance? That seems like the most likely cause of the problem. If so, this link might be helpful: https://stackoverflow.com/questions/36672935/why-retina-screen-coordinate-value-is-twice-the-value-of-pixel-value

[wkentaro]

Thanks! You're right. I'm using retina display, and below change fixed the issue.

commit f1869ed3efe6ae6caa599d286481678cde6c03d7
Author: Kentaro Wada <www.kentaro.wada@gmail.com>

    Fix size of widget.rect for retina display

diff --git a/scene_widget.py b/scene_widget.py
index 69bf0e0..9b2bb4f 100644
--- a/scene_widget.py
+++ b/scene_widget.py
@@ -17,6 +17,7 @@ class SceneGroup(pyglet.graphics.Group):
         camera_transform=None,
         view_transform=None,
         parent=None,
+        pixel_per_point=(1, 1),
     ):
         super().__init__(parent)
         self.rect = rect
@@ -33,23 +34,28 @@ class SceneGroup(pyglet.graphics.Group):
             view_transform = np.eye(4)
         self.view_transform = view_transform

+        self._pixel_per_point = pixel_per_point
+
     def set_state(self):
+        left = int(self.rect.left)
+        bottom = int(self.rect.bottom)
+        width = int(self.rect.width)
+        height = int(self.rect.height)
+
+        left = int(self._pixel_per_point[0] * left)
+        bottom = int(self._pixel_per_point[1] * bottom)
+        width = int(self._pixel_per_point[0] * width)
+        height = int(self._pixel_per_point[1] * height)
+
         glPushAttrib(GL_ENABLE_BIT)
         glEnable(GL_SCISSOR_TEST)
-        glScissor(
-            int(self.rect.left),
-            int(self.rect.bottom),
-            int(self.rect.width),
-            int(self.rect.height),
-        )
+        glScissor(left, bottom, width, height)

         self._mode = (GLint)()
         glGetIntegerv(GL_MATRIX_MODE, self._mode)
         self._viewport = (GLint * 4)()
         glGetIntegerv(GL_VIEWPORT, self._viewport)

-        left, bottom = int(self.rect.left), int(self.rect.bottom)
-        width, height = int(self.rect.width), int(self.rect.height)
         glViewport(left, bottom, width, height)
         glMatrixMode(GL_PROJECTION)
         glPushMatrix()
@@ -211,12 +217,15 @@ class SceneWidget(glooey.Widget):
         if self.vertex_list:
             return

+        pixel_per_point = np.array(self.window.get_viewport_size()) / \
+            np.array(self.window.get_size()),
         self.scene_group = SceneGroup(
             rect=self.rect,
             camera_fovy=self.scene.camera.fov[1],
             camera_transform=np.linalg.inv(self.scene.camera.transform),
             view_transform=self._trackball.pose.copy(),
             parent=self.group,
+            pixel_per_point=pixel_per_point,
         )

         node_names = self.scene.graph.nodes_geometry

https://github.com/wkentaro/trimesh-glooey/blob/master/scene_widget.py