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BG slide quality control, cropped PDF support

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This commit is contained in:
Daniel Petri Rocha 2022-06-29 14:07:28 +02:00
parent d510d6ad2c
commit 7d47641e2b
3 changed files with 27 additions and 27 deletions
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4
export-annotations/config/settings.json
View File

@ -6,6 +6,10 @@
"presDir": "/var/bigbluebutton",
"presAnnDropboxDir": "/tmp/pres-ann-dropbox"
},
"collector": {
"backgroundSlideDPI": 300,
"backgroundSlidePPI": 200
},
"process": {
"whiteboardTextEncoding": "utf-8",
"pointsPerInch": 72,

37
export-annotations/workers/collector.js
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@ -68,32 +68,25 @@ let exportJob = JSON.parse(job);
let pageNumber = p.page;
let svgFile = path.join(exportJob.presLocation, 'svgs', `slide${pageNumber}.svg`)
let outputFile = path.join(dropbox, `slide${pageNumber}`);
let svgFileExists = fs.existsSync(svgFile);
// CairoSVG doesn't handle transparent SVG and PNG embeds properly, e.g., in rasterized text.
// So textboxes may get a black background when downloading/exporting repeatedly.
// To avoid that, we take slides from the uploaded file, but probe the dimensions from the SVG
// To avoid that, we take slides from the uploaded file, but later probe the dimensions from the SVG
// so it matches what was shown in the browser -- Tldraw unfortunately uses absolute coordinates.
// This rasterizing process does mean a loss in quality.
if (svgFileExists) {
let dimensions = probe.sync(fs.readFileSync(svgFile));
let slideWidth = parseInt(dimensions.width, 10);
let slideHeight = parseInt(dimensions.height, 10);
let extract_png_from_pdf = [
'pdftocairo',
'-png',
'-f', pageNumber,
'-l', pageNumber,
'-scale-to-x', slideWidth,
'-scale-to-y', slideHeight,
'-singlefile',
pdfFile, outputFile,
].join(' ')
execSync(extract_png_from_pdf);
}
let extract_png_from_pdf = [
'pdftocairo',
'-png',
'-f', pageNumber,
'-l', pageNumber,
'-r', config.collector.backgroundSlidePPI,
'-singlefile',
'-cropbox',
pdfFile, outputFile,
].join(' ')
execSync(extract_png_from_pdf);
fs.copyFileSync(svgFile, path.join(dropbox, `slide${pageNumber}.svg`));
}
}

13
export-annotations/workers/process.js
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@ -744,6 +744,7 @@ let ghostScriptInput = ""
for (let currentSlide of pages) {
let backgroundImagePath = path.join(dropbox, `slide${currentSlide.page}`);
let svgFileExists = fs.existsSync(`${backgroundImagePath}.svg`)
let backgroundFormat = fs.existsSync(`${backgroundImagePath}.png`) ? 'png' : 'jpeg'
// Output dimensions in pixels even if stated otherwise (pt)
@ -751,7 +752,9 @@ for (let currentSlide of pages) {
// that would prevent loading file in memory
// Ideally, use dimensions provided by tldraw's background image asset
// (this is not yet always provided)
let dimensions = probe.sync(fs.readFileSync(`${backgroundImagePath}.${backgroundFormat}`));
let dimensions = svgFileExists ? 
probe.sync(fs.readFileSync(`${backgroundImagePath}.svg`)) :
probe.sync(fs.readFileSync(`${backgroundImagePath}.${backgroundFormat}`));
let slideWidth = parseInt(dimensions.width, 10);
let slideHeight = parseInt(dimensions.height, 10);
@ -761,8 +764,8 @@ for (let currentSlide of pages) {
.ele('svg', {
xmlns: 'http://www.w3.org/2000/svg',
'xmlns:xlink': 'http://www.w3.org/1999/xlink',
width: slideWidth,
height: slideHeight,
width: `${slideWidth}px`,
height: `${slideHeight}px`,
})
.dtd({
pubID: '-//W3C//DTD SVG 1.1//EN',
@ -770,8 +773,8 @@ for (let currentSlide of pages) {
})
.ele('image', {
'xlink:href': `file://${dropbox}/slide${currentSlide.page}.${backgroundFormat}`,
width: slideWidth,
height: slideHeight,
width: `${slideWidth}px`,
height: `${slideHeight}px`,
})
.up()
.ele('g', {