use a consistent text layouting algorithm (#1133)

* bug: measureText() is not consistent with measureTextHeight()

* use one layouting algorithm consistently

* plugin-print v0.16.2

---------

Co-authored-by: Ilia Pozdnyakov <[email protected]>

Author: hipstersmoothie

packages/plugin-print/src/index.js

@@ -1,7 +1,7 @@
 import Path from "path";
 import bMFont from "load-bmfont";
 import { isNodePattern, throwError } from "@jimp/utils";
-import { measureText, measureTextHeight } from "./measure-text";
+import { measureText, measureTextHeight, splitLines } from "./measure-text";
 
 function xOffsetBasedOnAlignment(constants, font, line, maxWidth, alignment) {
   if (alignment === constants.HORIZONTAL_ALIGN_LEFT) {
@@ -57,36 +57,6 @@ function printText(font, x, y, text, defaultCharWidth) {
   }
 }
 
-function splitLines(font, text, maxWidth) {
-  const words = text.split(" ");
-  const lines = [];
-  let currentLine = [];
-  let longestLine = 0;
-
-  words.forEach((word) => {
-    const line = [...currentLine, word].join(" ");
-    const length = measureText(font, line);
-
-    if (length <= maxWidth) {
-      if (length > longestLine) {
-        longestLine = length;
-      }
-
-      currentLine.push(word);
-    } else {
-      lines.push(currentLine);
-      currentLine = [word];
-    }
-  });
-
-  lines.push(currentLine);
-
-  return {
-    lines,
-    longestLine,
-  };
-}
-
 function loadPages(Jimp, dir, pages) {
   const newPages = pages.map((page) => {
     return Jimp.read(dir + "/" + page);

packages/plugin-print/src/measure-text.js

@@ -15,22 +15,38 @@ export function measureText(font, text) {
   return x;
 }
 
-export function measureTextHeight(font, text, maxWidth) {
+export function splitLines(font, text, maxWidth) {
   const words = text.split(" ");
-  let line = "";
-  let textTotalHeight = font.common.lineHeight;
+  const lines = [];
+  let currentLine = [];
+  let longestLine = 0;
+
+  words.forEach((word) => {
+    const line = [...currentLine, word].join(" ");
+    const length = measureText(font, line);
 
-  for (let n = 0; n < words.length; n++) {
-    const testLine = line + words[n] + " ";
-    const testWidth = measureText(font, testLine);
+    if (length <= maxWidth) {
+      if (length > longestLine) {
+        longestLine = length;
+      }
 
-    if (testWidth > maxWidth && n > 0) {
-      textTotalHeight += font.common.lineHeight;
-      line = words[n] + " ";
+      currentLine.push(word);
     } else {
-      line = testLine;
+      lines.push(currentLine);
+      currentLine = [word];
     }
-  }
+  });
+
+  lines.push(currentLine);
+
+  return {
+    lines,
+    longestLine,
+  };
+}
+
+export function measureTextHeight(font, text, maxWidth) {
+  const { lines } = splitLines(font, text, maxWidth);
 
-  return textTotalHeight;
+  return lines.length * font.common.lineHeight;
 }

packages/plugin-print/test/print.test.js

@@ -281,4 +281,15 @@ describe("Write text over image", function () {
 
     expectedImage.bitmap.data.should.be.deepEqual(image.bitmap.data);
   });
+
+  it("measureText is consistent with measureTextWidth", async () => {
+    const font = await jimp.loadFont(Jimp.FONT_SANS_16_BLACK);
+
+    const text = "n n n";
+    const width = jimp.measureText(font, text);
+    const height = jimp.measureTextHeight(font, text, width);
+    const lineHeight = jimp.measureTextHeight(font, text, Infinity);
+
+    height.should.be.deepEqual(lineHeight);
+  });
 });