DPI scaling in Windows: Difference between revisions

Revision as of 18:01, 1 September 2018

Revision as of 20:29, 1 September 2018

Line 3:

== Introduction ==

Since the 1980s, the [[Microsoft Windows]] operating system has set the default display "DPI" to 96 PPI, while [[Apple Inc|Apple]]/[[Macintosh]] computers have used a default of 72 PPI.<ref>

{{cite web|url=http://blogs.msdn.com/fontblog/archive/2005/11/08/490490.aspx|title=Where does 96 DPI come from in Windows?|last=Hitchcock|first=Greg|date=2005-10-08|work=Microsoft Developer Network Blog|publisher=Microsoft|accessdate=2009-11-07}}</ref> These default specifications arose out of the problems rendering standard fonts in the early display systems of the 1980s, including the [[IBM]]-based [[Color Graphics Adapter|CGA]], [[Enhanced Graphics Adapter|EGA]], [[VGA]] and [[8514]] displays as well as the [[Macintosh]] displays featured in the [[Macintosh 128K|128K]] computer and its successors. The choice of 72&nbsp;PPI by Macintosh for their displays arose from the convenient fact that the official 72 ''points per inch'' mirrored the 72 ''pixels per inch'' that appeared on their display screens. ([[Point (typography)|Points]] are a physical unit of measure in [[typography]], dating from the days of [[printing presses]], where 1 point by the [[Point (typography)#Current DTP point system|modern definition]] is 1/72 of the [[international inch]] (25.4&nbsp;mm), which therefore makes 1 point approximately 0.0139&nbsp;in or 352.8&nbsp;µm). Thus, the 72 pixels per inch seen on the display had exactly the same physical dimensions as the 72 points per inch later seen on a printout, with 1&nbsp;pt in printed text equal to 1&nbsp;px on the display screen. As it is, the Macintosh 128K featured a screen measuring 512 pixels in width by 342 pixels in height, and this corresponded to the width of standard office paper (512&nbsp;px ÷ 72&nbsp;px/in ≈ 7.1&nbsp;in, with a 0.7&nbsp;in margin down each side when assuming [[Letter paper|8.5&nbsp;in × 11&nbsp;in North American paper size]] (in Europe, it's 21cm21&nbsp;cm x 30cm30&nbsp;cm - called "A4". B5 is 176 millimeters x 250 millimeters)).{{citation needed|date=April 2014}}

A consequence of Apple's decision was that the widely used 10-point fonts from the typewriter era had to be allotted 10 display pixels in [[Em (typography)|em]] height, and 5 display pixels in ''[[x-height]]''. This is technically described as 10 ''pixels per em'' (''PPEm''). This made 10-point fonts be rendered crudely and made them difficult to read on the display screen, particularly the lowercase characters. Furthermore, there was the consideration that computer screens are typically viewed (at a desk) at a distance 30% greater than printed materials, causing a mismatch between the perceived sizes seen on the computer screen and those on the printouts.{{citation needed|date=April 2014}}

Line 22:

== Before Windows XP ==

Since [[Windows 95]], Windows provides an option to set the font size by Display Properties>Settings>Advanced. The default options are 96 DPI (standard), 120 DPI and custom, wherein one can set the desired font zoom. In this mode, only text is scaled, and often improperly, as most applications back then considered 96 DPI as the standard. [[File:Windows 2000 scaling at 200%.png|thumb|Windows 2000 desktop at 200%, with [[Windows Explorer]] and [[Internet Explorer 5|Internet Explorer 5]]. Click to see full image.]]

== Windows XP ==

Windows XP introduced the GDI+ library which allows resolution-independent text scaling. [[Windows XP]] scales up the font and UI object sizes as if you'd gone and adjusted your theme's size settings, which can cause some graphical anomalies in some apps that're hardcoded to use default font and icon sizes. ,<ref>https://superuser.com/questions/134986/what-is-the-downside-to-windows-xp-style-dpi-scaling-in-windows-7</ref>, basically scaling up text which causes clipping for those which are not designed to deal with High-DPI applications. [[File:Windows XP scaling at 200%.png|thumb|Scaling at Windows XP with 200%, with Windows Explorer, Internet Explorer 6, Tablet PC overview and [[Volume Control]] in foreground. Click to see full image]]

== Windows Vista, 7 and 8==

[[Windows Vista]] includes the now-ubiquitous concept of DPI virtualisation. In this mode, apps are rendered in a 96 DPI buffer off the screen and then upscaled to match the current DPI. This, while ensuring that icons and text stay intact and in the same position, introduces blurriness which is due to the fact that everything is essentially zoomed.

== Windows 8.1 ==

The maximum scaling level was increased from 150% to 200%, and it is now possible to independently set scaling level for each monitor. <ref>https://blogs.windows.com/windowsexperience/2013/07/15/windows-8-1-dpi-scaling-enhancements/

</ref>

== References ==

<references />

{{Uncategorized|date=September 2018}}