[wpigui] Add GetDistSquared and MaxFit functions

These utility functions were moved from halsim_gui.

wpigui/src/main/native/cpp/wpigui.cpp

@@ -413,4 +413,19 @@ bool gui::CreateTextureFromImage(const unsigned char* data, int len,
   return true;
 }
 
+void gui::MaxFit(ImVec2* min, ImVec2* max, float width, float height) {
+  float destWidth = max->x - min->x;
+  float destHeight = max->y - min->y;
+  if (width == 0 || height == 0) return;
+  if (destWidth * height > destHeight * width) {
+    float outputWidth = width * destHeight / height;
+    min->x += (destWidth - outputWidth) / 2;
+    max->x -= (destWidth - outputWidth) / 2;
+  } else {
+    float outputHeight = height * destWidth / width;
+    min->y += (destHeight - outputHeight) / 2;
+    max->y -= (destHeight - outputHeight) / 2;
+  }
+}
+
 }  // namespace wpi

wpigui/src/main/native/include/wpigui.h

@@ -351,4 +351,29 @@ class Texture {
   int m_height = 0;
 };
 
+/**
+ * Get square of distance between two ImVec2's.
+ *
+ * @param a first ImVec
+ * @param b second ImVec
+ *
+ * @return Distance^2 between a and b.
+ */
+inline float GetDistSquared(const ImVec2& a, const ImVec2& b) {
+  float deltaX = b.x - a.x;
+  float deltaY = b.y - a.y;
+  return deltaX * deltaX + deltaY * deltaY;
+}
+
+/**
+ * Maximize fit in "window" while preserving aspect ratio.  Min and max
+ * passed-in values are modified such that the object maximally fits.
+ *
+ * @param min upper left corner of window (modified to fit)
+ * @param max lower right corner of window (modified to fit)
+ * @param width width of object to fit
+ * @param height height of object to fit
+ */
+void MaxFit(ImVec2* min, ImVec2* max, float width, float height);
+
 }  // namespace wpi::gui