From e07b093dfcada84aa4a11b4aa80cfa461051702e Mon Sep 17 00:00:00 2001
From: Pierre Hubert <pierre.git@communiquons.org>
Date: Sat, 26 Aug 2023 13:17:04 +0200
Subject: [PATCH] Fix text size rendering

---
 geneit_app/src/utils/render_utils.ts          | 31 +++++++++++++++++++
 .../simple_family_tree/SimpleFamilyTree.tsx   | 24 ++++++++------
 2 files changed, 45 insertions(+), 10 deletions(-)
 create mode 100644 geneit_app/src/utils/render_utils.ts

diff --git a/geneit_app/src/utils/render_utils.ts b/geneit_app/src/utils/render_utils.ts
new file mode 100644
index 0000000..0047c25
--- /dev/null
+++ b/geneit_app/src/utils/render_utils.ts
@@ -0,0 +1,31 @@
+let canvas: HTMLCanvasElement = document.createElement("canvas");
+let charLen: Map<string, Map<string, number>> = new Map();
+
+/**
+ * Uses canvas.measureText to compute and return the width of the given text of given font in pixels.
+ *
+ * @param {String} text The text to be rendered.
+ * @param {String} font The css font descriptor that text is to be rendered with (e.g. "bold 14px verdana").
+ *
+ * @see https://stackoverflow.com/questions/118241/calculate-text-width-with-javascript/21015393#21015393
+ */
+function computeTextWidth(text: string, font: string) {
+  // re-use canvas object for better performance
+  const context = canvas.getContext("2d")!;
+  context.font = font;
+  const metrics = context.measureText(text);
+  return metrics.width;
+}
+
+export function getTextWidth(text: string, font: string) {
+  if (!charLen.has(font)) charLen.set(font, new Map());
+  const ref = charLen.get(font)!;
+
+  let size = 0;
+  for (const c of text) {
+    if (!ref.has(c)) ref.set(c, computeTextWidth(c, font));
+    size += ref.get(c)!;
+  }
+  console.log(text, size);
+  return size;
+}
diff --git a/geneit_app/src/widgets/simple_family_tree/SimpleFamilyTree.tsx b/geneit_app/src/widgets/simple_family_tree/SimpleFamilyTree.tsx
index d8fef8e..b68a0b4 100644
--- a/geneit_app/src/widgets/simple_family_tree/SimpleFamilyTree.tsx
+++ b/geneit_app/src/widgets/simple_family_tree/SimpleFamilyTree.tsx
@@ -2,18 +2,20 @@ import React from "react";
 import { Couple } from "../../api/CoupleApi";
 import { Member } from "../../api/MemberApi";
 import { FamilyTreeNode } from "../../utils/family_tree";
+import { getTextWidth } from "../../utils/render_utils";
 
 const FACE_WIDTH = 60;
 const FACE_HEIGHT = 70;
+const FACE_TEXT_SPACING = 2;
 
-const CARD_HEIGHT = 110;
+const CARD_HEIGHT = 103;
 const SPOUSE_SPACING = 10;
 const CARD_SPACING = 20;
 const SIBLINGS_SPACING = 20;
-const LEVEL_SPACING = 20;
+const LEVEL_SPACING = 25;
 
-const NAME_CHAR_W = 7.1428;
-const BIRTH_CHAR_W = 5;
+const NAME_FONT = "13px Roboto";
+const BIRTH_FONT = "10px Roboto";
 
 interface SimpleTreeSpouseInfo {
   member: Member;
@@ -31,8 +33,8 @@ interface SimpleTreeNode {
  * Get the width of a member card
  */
 function memberCardWidth(m: Member): number {
-  const nameWidth = m.fullName.length * NAME_CHAR_W;
-  const birthDeathWidth = m.displayBirthDeath.length * BIRTH_CHAR_W;
+  const nameWidth = getTextWidth(m.fullName, NAME_FONT);
+  const birthDeathWidth = getTextWidth(m.displayBirthDeath, BIRTH_FONT);
   return Math.max(FACE_WIDTH, nameWidth, birthDeathWidth);
 }
 
@@ -170,7 +172,7 @@ function NodeArea(p: {
             node={n}
           />
         );
-        downXOffset += n.width;
+        downXOffset += n.width + SIBLINGS_SPACING;
         return el;
       })}
     </>
@@ -203,18 +205,20 @@ function MemberCard(p: {
       )}
 
       {/* Member text */}
-      <text y={FACE_HEIGHT}>
+      <text y={FACE_HEIGHT + FACE_TEXT_SPACING}>
         <tspan
-          x={center(w, p.member.fullName.length * NAME_CHAR_W)}
+          x={center(w, getTextWidth(p.member.fullName, NAME_FONT))}
           dy="14"
           font-size="13"
+          fontFamily="Roboto"
         >
           {p.member.fullName}
         </tspan>
         <tspan
-          x={center(w, p.member.displayBirthDeath.length * BIRTH_CHAR_W)}
+          x={center(w, getTextWidth(p.member.displayBirthDeath, BIRTH_FONT))}
           dy="14"
           font-size="10"
+          fontFamily="Roboto"
         >
           {p.member.displayBirthDeath}
         </tspan>