SlideShare has abandoned Flash in favor of HTML5
SlideShare, the most popular slide hosting service on the Internet, yesterday announced the most significant change in its history. PowerPoint, PDF, Keynote, or OpenOffice presentations and documents are now rendered and rendered in HTML5 instead of Flash.
The developers say that five years ago it was impossible to imagine creating a service like Youtube or SlideShare without using Flash, but now the web is finally ripe for this.
There are three reasons for the upgrade. First, HTML5 presentations are displayed on all devices, including smartphones / tablets, iPhone / iPad and Android, and on the desktop - and this is the same file. Thus, the amount of data on the hosting decreases and you can save on CDN. Secondly, documents are 40% smaller and load 30% faster. Thirdly, documents are now indexed by search engines. The text is easily highlighted with a mouse and copied, which has always been difficult with Flash.
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Work on the Flash → HTML5 upgrade lasted six months. The hardest thing was processing fonts. It was necessary to make support for rendering various fonts that are not installed on the client machine. But this problem has been solved, so if you reinvent your own font and upload a PDF to it with it, it will be perfectly displayed in SlideShare.
Another problem was the exact positioning of the text due to differences in browsers and ligatures of different fonts. For example, PDF counts coordinates from the bottom left corner, HTML from the top left. These standards use different measurement systems, and different browsers also work unequally with them.
To control the same PDF and HTML rendering, a separate error control system was created, which compares the images obtained using the two rendering methods and calculates the degree of difference. If the indicator is above a certain threshold, then instead of HTML5 slides are issued with PNG pictures. Developers believe that it is better to sacrifice a single HTML5 approach than the appearance of the document.
All SlideShare infrastructure runs on Amazon EC2. Now, hundreds of virtual servers need to work well to convert several million documents from Flash to HTML5 that have accumulated on SlideShare hosting over the five years of its existence. The developers hope that the process will be completed before the end of this year. After this point, all content will be rendered in HTML5.
Bonus
A selection of the best SlideShare HTML5 presentations , now in HTML5 :)
The developers say that five years ago it was impossible to imagine creating a service like Youtube or SlideShare without using Flash, but now the web is finally ripe for this.
There are three reasons for the upgrade. First, HTML5 presentations are displayed on all devices, including smartphones / tablets, iPhone / iPad and Android, and on the desktop - and this is the same file. Thus, the amount of data on the hosting decreases and you can save on CDN. Secondly, documents are 40% smaller and load 30% faster. Thirdly, documents are now indexed by search engines. The text is easily highlighted with a mouse and copied, which has always been difficult with Flash.
')
Work on the Flash → HTML5 upgrade lasted six months. The hardest thing was processing fonts. It was necessary to make support for rendering various fonts that are not installed on the client machine. But this problem has been solved, so if you reinvent your own font and upload a PDF to it with it, it will be perfectly displayed in SlideShare.
Another problem was the exact positioning of the text due to differences in browsers and ligatures of different fonts. For example, PDF counts coordinates from the bottom left corner, HTML from the top left. These standards use different measurement systems, and different browsers also work unequally with them.
To control the same PDF and HTML rendering, a separate error control system was created, which compares the images obtained using the two rendering methods and calculates the degree of difference. If the indicator is above a certain threshold, then instead of HTML5 slides are issued with PNG pictures. Developers believe that it is better to sacrifice a single HTML5 approach than the appearance of the document.
All SlideShare infrastructure runs on Amazon EC2. Now, hundreds of virtual servers need to work well to convert several million documents from Flash to HTML5 that have accumulated on SlideShare hosting over the five years of its existence. The developers hope that the process will be completed before the end of this year. After this point, all content will be rendered in HTML5.
Bonus
A selection of the best SlideShare HTML5 presentations , now in HTML5 :)
Source: https://habr.com/ru/post/129299/
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