From ba8c996623c66703d5b2b97cfa3850486a40d057 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Mon, 5 Jun 2023 12:15:41 +0200
Subject: [PATCH] [Editor] Guess font size and color from the AS of FreeText
annotations
---
src/core/annotation.js | 16 ++-
src/core/default_appearance.js | 87 +++++++++++++++++
test/unit/default_appearance_spec.js | 140 +++++++++++++++++++++++++++
3 files changed, 238 insertions(+), 5 deletions(-)
diff --git a/src/core/annotation.js b/src/core/annotation.js
index 054487d57..7937479d4 100644
--- a/src/core/annotation.js
+++ b/src/core/annotation.js
@@ -48,6 +48,7 @@ import {
createDefaultAppearance,
FakeUnicodeFont,
getPdfColor,
+ parseAppearanceStream,
parseDefaultAppearance,
} from "./default_appearance.js";
import { Dict, isName, Name, Ref, RefSet } from "./primitives.js";
@@ -3545,20 +3546,25 @@ class FreeTextAnnotation extends MarkupAnnotation {
const { xref } = params;
this.data.annotationType = AnnotationType.FREETEXT;
this.setDefaultAppearance(params);
- if (!this.appearance && this._isOffscreenCanvasSupported) {
+ if (this.appearance) {
+ const { fontColor, fontSize } = parseAppearanceStream(this.appearance);
+ this.data.defaultAppearanceData.fontColor = fontColor;
+ this.data.defaultAppearanceData.fontSize = fontSize || 10;
+ } else if (this._isOffscreenCanvasSupported) {
const strokeAlpha = params.dict.get("CA");
const fakeUnicodeFont = new FakeUnicodeFont(xref, "sans-serif");
- const fontData = this.data.defaultAppearanceData;
+ this.data.defaultAppearanceData.fontSize ||= 10;
+ const { fontColor, fontSize } = this.data.defaultAppearanceData;
this.appearance = fakeUnicodeFont.createAppearance(
this._contents.str,
this.rectangle,
this.rotation,
- fontData.fontSize || 10,
- fontData.fontColor,
+ fontSize,
+ fontColor,
strokeAlpha
);
this._streams.push(this.appearance, FakeUnicodeFont.toUnicodeStream);
- } else if (!this._isOffscreenCanvasSupported) {
+ } else {
warn(
"FreeTextAnnotation: OffscreenCanvas is not supported, annotation may not render correctly."
);
diff --git a/src/core/default_appearance.js b/src/core/default_appearance.js
index e886d3184..2816fc90e 100644
--- a/src/core/default_appearance.js
+++ b/src/core/default_appearance.js
@@ -87,6 +87,92 @@ function parseDefaultAppearance(str) {
return new DefaultAppearanceEvaluator(str).parse();
}
+class AppearanceStreamEvaluator extends EvaluatorPreprocessor {
+ constructor(stream) {
+ super(stream);
+ this.stream = stream;
+ }
+
+ parse() {
+ const operation = {
+ fn: 0,
+ args: [],
+ };
+ let result = {
+ scaleFactor: 1,
+ fontSize: 0,
+ fontName: "",
+ fontColor: /* black = */ new Uint8ClampedArray(3),
+ };
+ let breakLoop = false;
+ const stack = [];
+
+ try {
+ while (true) {
+ operation.args.length = 0; // Ensure that `args` it's always reset.
+
+ if (breakLoop || !this.read(operation)) {
+ break;
+ }
+ const { fn, args } = operation;
+
+ switch (fn | 0) {
+ case OPS.save:
+ stack.push({
+ scaleFactor: result.scaleFactor,
+ fontSize: result.fontSize,
+ fontName: result.fontName,
+ fontColor: result.fontColor.slice(),
+ });
+ break;
+ case OPS.restore:
+ result = stack.pop() || result;
+ break;
+ case OPS.setTextMatrix:
+ result.scaleFactor *= Math.hypot(args[0], args[1]);
+ break;
+ case OPS.setFont:
+ const [fontName, fontSize] = args;
+ if (fontName instanceof Name) {
+ result.fontName = fontName.name;
+ }
+ if (typeof fontSize === "number" && fontSize > 0) {
+ result.fontSize = fontSize * result.scaleFactor;
+ }
+ break;
+ case OPS.setFillRGBColor:
+ ColorSpace.singletons.rgb.getRgbItem(args, 0, result.fontColor, 0);
+ break;
+ case OPS.setFillGray:
+ ColorSpace.singletons.gray.getRgbItem(args, 0, result.fontColor, 0);
+ break;
+ case OPS.setFillColorSpace:
+ ColorSpace.singletons.cmyk.getRgbItem(args, 0, result.fontColor, 0);
+ break;
+ case OPS.showText:
+ case OPS.showSpacedText:
+ case OPS.nextLineShowText:
+ case OPS.nextLineSetSpacingShowText:
+ breakLoop = true;
+ break;
+ }
+ }
+ } catch (reason) {
+ warn(`parseAppearanceStream - ignoring errors: "${reason}".`);
+ }
+ this.stream.reset();
+ delete result.scaleFactor;
+
+ return result;
+ }
+}
+
+// Parse appearance stream to extract font and color information.
+// It returns the font properties used to render the first text object.
+function parseAppearanceStream(stream) {
+ return new AppearanceStreamEvaluator(stream).parse();
+}
+
function getPdfColor(color, isFill) {
if (color[0] === color[1] && color[1] === color[2]) {
const gray = color[0] / 255;
@@ -368,5 +454,6 @@ export {
createDefaultAppearance,
FakeUnicodeFont,
getPdfColor,
+ parseAppearanceStream,
parseDefaultAppearance,
};
diff --git a/test/unit/default_appearance_spec.js b/test/unit/default_appearance_spec.js
index 7bd422736..53b49ed5b 100644
--- a/test/unit/default_appearance_spec.js
+++ b/test/unit/default_appearance_spec.js
@@ -15,8 +15,10 @@
import {
createDefaultAppearance,
+ parseAppearanceStream,
parseDefaultAppearance,
} from "../../src/core/default_appearance.js";
+import { StringStream } from "../../src/core/stream.js";
describe("Default appearance", function () {
describe("parseDefaultAppearance and createDefaultAppearance", function () {
@@ -50,4 +52,142 @@ describe("Default appearance", function () {
});
});
});
+
+ describe("parseAppearanceStream", () => {
+ it("should parse a FreeText (from Acrobat) appearance", () => {
+ const appearance = new StringStream(`
+ 0 w
+ 46.5 621.0552 156.389 18.969 re
+ n
+ q
+ 1 0 0 1 0 0 cm
+ 46.5 621.0552 156.389 18.969 re
+ W
+ n
+ 0 g
+ 1 w
+ BT
+ /Helv 14 Tf
+ 0.419998 0.850006 0.160004 rg
+ 46.5 626.77 Td
+ (Hello ) Tj
+ 35.793 0 Td
+ (World ) Tj
+ 40.448 0 Td
+ (from ) Tj
+ 31.89 0 Td
+ (Acrobat) Tj
+ ET
+ Q`);
+ const result = {
+ fontSize: 14,
+ fontName: "Helv",
+ fontColor: new Uint8ClampedArray([107, 217, 41]),
+ };
+ expect(parseAppearanceStream(appearance)).toEqual(result);
+ expect(appearance.pos).toEqual(0);
+ });
+
+ it("should parse a FreeText (from Firefox) appearance", () => {
+ const appearance = new StringStream(`
+ q
+ 0 0 203.7 28.3 re W n
+ BT
+ 1 0 0 1 0 34.6 Tm 0 Tc 0.93 0.17 0.44 rg
+ /Helv 18 Tf
+ 0 -24.3 Td (Hello World From Firefox) Tj
+ ET
+ Q`);
+ const result = {
+ fontSize: 18,
+ fontName: "Helv",
+ fontColor: new Uint8ClampedArray([237, 43, 112]),
+ };
+ expect(parseAppearanceStream(appearance)).toEqual(result);
+ expect(appearance.pos).toEqual(0);
+ });
+
+ it("should parse a FreeText (from Preview) appearance", () => {
+ const appearance = new StringStream(`
+ q Q q 2.128482 2.128482 247.84 26 re W n /Cs1 cs 0.52799 0.3071 0.99498 sc
+ q 1 0 0 -1 -108.3364 459.8485 cm BT 22.00539 0 0 -22.00539 110.5449 452.72
+ Tm /TT1 1 Tf [ (H) -0.2 (e) -0.2 (l) -0.2 (l) -0.2 (o) -0.2 ( ) 0.2 (W) 17.7
+ (o) -0.2 (rl) -0.2 (d) -0.2 ( ) 0.2 (f) 0.2 (ro) -0.2 (m ) 0.2 (Pre) -0.2
+ (vi) -0.2 (e) -0.2 (w) ] TJ ET Q Q`);
+ const result = {
+ fontSize: 22.00539,
+ fontName: "TT1",
+ fontColor: new Uint8ClampedArray([0, 0, 0]),
+ };
+ expect(parseAppearanceStream(appearance)).toEqual(result);
+ expect(appearance.pos).toEqual(0);
+ });
+
+ it("should parse a FreeText (from Edge) appearance", () => {
+ const appearance = new StringStream(`
+ q
+ 0 0 292.5 18.75 re W n
+ BT
+ 0 Tc
+ 0.0627451 0.486275 0.0627451 rg
+ 0 3.8175 Td
+ /Helv 16.5 Tf
+ (Hello World from Edge without Acrobat) Tj
+ ET
+ Q`);
+ const result = {
+ fontSize: 16.5,
+ fontName: "Helv",
+ fontColor: new Uint8ClampedArray([16, 124, 16]),
+ };
+ expect(parseAppearanceStream(appearance)).toEqual(result);
+ expect(appearance.pos).toEqual(0);
+ });
+
+ it("should parse a FreeText (from Foxit) appearance", () => {
+ const appearance = new StringStream(`
+ q
+ /Tx BMC
+ 0 -22.333 197.667 22.333 re
+ W
+ n
+ BT
+ 0.584314 0.247059 0.235294 rg
+ 0 -18.1 Td
+ /FXF0 20 Tf
+ (Hello World from Foxit) Tj
+ ET
+ EMC
+ Q`);
+ const result = {
+ fontSize: 20,
+ fontName: "FXF0",
+ fontColor: new Uint8ClampedArray([149, 63, 60]),
+ };
+ expect(parseAppearanceStream(appearance)).toEqual(result);
+ expect(appearance.pos).toEqual(0);
+ });
+
+ it("should parse a FreeText (from Okular) appearance", () => {
+ const appearance = new StringStream(`
+ q
+ 0.00 0.00 172.65 41.46 re W n
+ 0.00000 0.33333 0.49804 rg
+ BT 1 0 0 1 0.00 41.46 Tm
+ /Invalid_font 18.00 Tf
+ 0.00 -18.00 Td
+ (Hello World from) Tj
+ /Invalid_font 18.00 Tf
+ 0.00 -18.00 Td
+ (Okular) Tj
+ ET Q`);
+ const result = {
+ fontSize: 18,
+ fontName: "Invalid_font",
+ fontColor: new Uint8ClampedArray([0, 85, 127]),
+ };
+ expect(parseAppearanceStream(appearance)).toEqual(result);
+ expect(appearance.pos).toEqual(0);
+ });
+ });
});