Sweet Home 3D Forum - View Thread - Move selection by an exact distance

From ae3f3435dde25fee5f9213c9c0333d78c641a49c Mon Sep 17 00:00:00 2001
From: Vladimir Panteleev <[email protected]>
Date: Sat, 15 Apr 2023 22:20:06 +0000
Subject: [PATCH] Made the arrow keys move the selection by distances aligned
 to user units

Arrow keys move selected items by a distance which depends on the zoom
level (scale), however this can be a little arbitrary.

Since the user operates on a grid with length values based in a
real-world system of measurements, it's usually more useful to allow
operating in terms of those values. In practical terms, this means
that users are more likely to find useful to move an item by 1 cm, as
opposed to e.g. 1.025641025 cm.

Make the arrow keys do this, by using a function which calculates a
scale value such that a unit distance will be greater than a pixel but
aligned to the user's preferred system of measurements.
---
 .../sweethome3d/swing/PlanComponent.java      | 36 ++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/com/eteks/sweethome3d/swing/PlanComponent.java b/src/com/eteks/sweethome3d/swing/PlanComponent.java
index 7d91535..ed75adb 100644
--- a/src/com/eteks/sweethome3d/swing/PlanComponent.java
+++ b/src/com/eteks/sweethome3d/swing/PlanComponent.java
@@ -1595,7 +1595,7 @@ public class PlanComponent extends JComponent implements PlanView, Scrollable, P
       }
 
       public void actionPerformed(ActionEvent ev) {
-        controller.moveSelection(this.dx / getScale(), this.dy / getScale());
+        controller.moveSelection(this.dx / getAlignedScale(), this.dy / getAlignedScale());
       }
     }
     // Toggle magnetism action
@@ -5584,6 +5584,40 @@ public class PlanComponent extends JComponent implements PlanView, Scrollable, P
     return this.scale;
   }
 
+  private static final float[] metricScaleSteps = {
+    0.01f, 0.025f, 0.05f,
+    0.1f, 0.25f, 0.5f,
+    1f, 2.5f, 5f,
+    10f, 25f, 50f,
+    100f, 250f, 500f,
+    1000f, 2500f, 5000f,
+    10000f, 25000f, 50000f
+  };
+
+  private static final float[] imperialScaleSteps = {
+    2.54f / 12 / 12, 2.54f / 12 / 4, 2.54f / 12 / 2,
+    2.54f / 12, 2.54f / 4, 2.54f / 2,
+    2.54f, 2.54f * 3, 2.54f * 6,
+    2.54f * 12, 2.54f * 12 * 3, 2.54f * 12 * 6,
+    2.54f * 12 * 12, 2.54f * 12 * 12 * 3, 2.54f * 12 * 12 * 6,
+    2.54f * 12 * 12 * 12, 2.54f * 12 * 12 * 12 * 3, 2.54f * 12 * 12 * 12 * 6,
+    2.54f * 12 * 12 * 12 * 12
+  };
+
+  /**
+   * Returns a scale value close to getScale(), but aligned to the user's preferred measurement units.
+   */
+  public float getAlignedScale() {
+    LengthUnit lengthUnit = this.preferences.getLengthUnit();
+    float[] scaleSteps = lengthUnit.isMetric() ? metricScaleSteps : imperialScaleSteps;
+    float pixelLength = getPixelLength();
+    for (int i = 0; i < scaleSteps.length; i++) {
+      if (scaleSteps >= pixelLength)
+        return 1 / scaleSteps / this.resolutionScale;
+    }
+    return this.scale;
+  }
+
   /**
    * Sets the scale used to display the plan.
    * If this component is displayed in a viewport the view position is updated
-- 
2.40.0