From 6cc6e138925a0f001bc92bc091a1cba611ab6d01 Mon Sep 17 00:00:00 2001
From: Daishi Kato <dai-shi@users.noreply.github.com>
Date: Thu, 9 Jul 2020 22:22:10 +0900
Subject: [PATCH] adjust font baseline on resize (#1820)

* adjust font baseline on resize

* simplify font scaling on resize

* fix: resizing text to avoid glitchy behavior

* make text resizing deterministic

* no TEXT_WIDTH_PADDING hack

Co-authored-by: dwelle <luzar.david@gmail.com>
---
 src/element/resizeElements.ts | 41 ++++++++++-------------------------
 1 file changed, 11 insertions(+), 30 deletions(-)

diff --git a/src/element/resizeElements.ts b/src/element/resizeElements.ts
index 835591957..e39263e78 100644
--- a/src/element/resizeElements.ts
+++ b/src/element/resizeElements.ts
@@ -207,45 +207,26 @@ const rescalePointsInElement = (
       }
     : {};
 
-// This is not computationally ideal, but can't be helped.
+const MIN_FONT_SIZE = 1;
+
 const measureFontSizeFromWH = (
   element: NonDeleted<ExcalidrawTextElement>,
   nextWidth: number,
   nextHeight: number,
 ): { size: number; baseline: number } | null => {
-  let scale = Math.min(nextWidth / element.width, nextHeight / element.height);
-  let nextFontSize = element.fontSize * scale;
-  let metrics = measureText(
-    element.text,
-    getFontString({ fontSize: nextFontSize, fontFamily: element.fontFamily }),
-  );
-  if (metrics.width - nextWidth < 1 && metrics.height - nextHeight < 1) {
-    return { size: nextFontSize, baseline: metrics.baseline };
-  }
-  // second measurement
-  scale = Math.min(
-    Math.min(nextWidth, metrics.width) / element.width,
-    Math.min(nextHeight, metrics.height) / element.height,
-  );
-  nextFontSize = element.fontSize * scale;
-  metrics = measureText(
-    element.text,
-    getFontString({ fontSize: nextFontSize, fontFamily: element.fontFamily }),
-  );
-  if (metrics.width - nextWidth < 1 && metrics.height - nextHeight < 1) {
-    return { size: nextFontSize, baseline: metrics.baseline };
+  // We only use width to scale font on resize
+  const nextFontSize = element.fontSize * (nextWidth / element.width);
+  if (nextFontSize < MIN_FONT_SIZE) {
+    return null;
   }
-  // third measurement
-  scale *= 0.99; // just heuristics
-  nextFontSize = element.fontSize * scale;
-  metrics = measureText(
+  const metrics = measureText(
     element.text,
     getFontString({ fontSize: nextFontSize, fontFamily: element.fontFamily }),
   );
-  if (metrics.width - nextWidth < 1 && metrics.height - nextHeight < 1) {
-    return { size: nextFontSize, baseline: metrics.baseline };
-  }
-  return null;
+  return {
+    size: nextFontSize,
+    baseline: metrics.baseline + (nextHeight - metrics.height),
+  };
 };
 
 const getSidesForResizeHandle = (