From df3e2dc3e28cc2d89737c4e332a18220c83244b3 Mon Sep 17 00:00:00 2001
From: Pierre-Yves Nicolas <6371790+pynicolas@users.noreply.github.com>
Date: Mon, 6 Oct 2025 14:52:18 +0200
Subject: [PATCH] Geometry: use Double instead of Int to scale precisely

---
 .../main/java/org/fairscan/app/DocumentDetection.kt |  4 ++--
 app/src/main/java/org/fairscan/app/Geometry.kt      | 13 +++++++------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/app/src/main/java/org/fairscan/app/DocumentDetection.kt b/app/src/main/java/org/fairscan/app/DocumentDetection.kt
index 8ab82ad..c475d36 100644
--- a/app/src/main/java/org/fairscan/app/DocumentDetection.kt
+++ b/app/src/main/java/org/fairscan/app/DocumentDetection.kt
@@ -67,7 +67,7 @@ fun detectDocumentQuad(mask: Bitmap, minQuadAreaRatio: Double = 0.02): Quad? {
         return null
     }
 
-    val vertices = biggest?.toList()?.map { Point(it.x.toInt(), it.y.toInt()) }
+    val vertices = biggest?.toList()?.map { Point(it.x, it.y) }
     return if (vertices?.size == 4) createQuad(vertices) else null
 }
 
@@ -162,6 +162,6 @@ private fun toBitmap(mat: Mat): Bitmap {
 }
 
 fun Point.toCv(): org.opencv.core.Point {
-    return org.opencv.core.Point(x.toDouble(), y.toDouble())
+    return org.opencv.core.Point(x, y)
 }
 
diff --git a/app/src/main/java/org/fairscan/app/Geometry.kt b/app/src/main/java/org/fairscan/app/Geometry.kt
index ca9ba35..76b3aa0 100644
--- a/app/src/main/java/org/fairscan/app/Geometry.kt
+++ b/app/src/main/java/org/fairscan/app/Geometry.kt
@@ -15,9 +15,10 @@
 package org.fairscan.app
 
 import kotlin.math.atan2
-import kotlin.math.sqrt
 
-data class Point(val x: Int, val y: Int)
+data class Point(val x: Double, val y: Double) {
+    constructor(x: Int, y: Int) : this (x.toDouble(), y.toDouble())
+}
 
 data class Line(val from: Point, val to: Point) {
     fun norm(): Double {
@@ -28,7 +29,7 @@ data class Line(val from: Point, val to: Point) {
 fun norm(p1: Point, p2: Point): Double {
     val dx = (p2.x - p1.x)
     val dy = (p2.y - p1.y)
-    return sqrt(dx.toDouble() * dx + dy * dy)
+    return kotlin.math.hypot(dx, dy)
 }
 
 data class Quad(
@@ -72,8 +73,8 @@ fun createQuad(vertices: List<Point>): Quad {
     val cy = vertices.map { it.y }.average()
 
     // Sort by angle from centroid (clockwise)
-    val sorted = vertices.sortedWith(compareBy<Point> {
-        atan2((it.y - cy).toDouble(), (it.x - cx).toDouble())
+    val sorted = vertices.sortedWith(compareBy {
+        atan2(it.y - cy, it.x - cx)
     })
 
     return Quad(sorted[0], sorted[1], sorted[2], sorted[3])
@@ -91,5 +92,5 @@ fun Quad.scaledTo(fromWidth: Int, fromHeight: Int, toWidth: Int, toHeight: Int):
 }
 
 fun Point.scaled(scaleX: Float, scaleY: Float): Point {
-    return Point((x * scaleX).toInt(), (y * scaleY).toInt())
+    return Point((x * scaleX), (y * scaleY))
 }