On 2012/04/25 07:24 (GMT-0400) Carl Hartung composed:
At 120 DPI a bitmap of 360 x 360 pixels displays as a 3" square
At 96 DPI the same graphic displays as a 3.75" square (larger)
At 72 DPI it displays as a 5" square ... much larger
This is the "zoom" effect that Felix alluded to.
Accurate as what you wrote certainly is, describing it has you have not infrequently causes confusion among users trying to use it in the context of attempting to apply an overall desktop zoom effect. Certainly as DPI goes up for any given resolution, the physical size of a bitmap goes down. The DE scales according to DPI, which is easier with fonts than images. A 12pt font at 96 DPI nominally has about 128 pixels to work with to draw each glyph (16px tall, 8px wide). At a 25% DPI increase to 120 from 96, the nominal available pixel count for a 12pt font jumps to 20px tall x 10 px wide, 200 total, an increase of 56.25%. This difference is in no small part responsible for font quality increase as pixel density goes up. Some people find this difference to be an unappealing increase in stroke weight at commonly used sizes, seeing it as undesirable bolding, until they get used to the naturally reduced or eliminated jaggies and learn to appreciate the more accurately drawn glyphs for what they are - higher overall quality. For icons, the required zoom is traditionally implemented via a selection of discrete images selected according to availability and need. Usually the selection is limited, so going too high in DPI will at a point cease to be able to provide icons sized in reasonably close proportion to the associate text they are typically coupled with. Vector icons are the solution to this problem, but I've yet to see evidence of widespread implementation of vector icons. The biggest drawback to forcing DPI as a desktop zoom effect is that there is no way to make bitmaps bigger except via methods that cannot do more than estimate the required additional information that doesn't exist. There's simply no substitute for having enough pixels in the original image if physical size is to be preserved as density rises. OTOH, there isn't really a whole lot of difference in perceived quality between a bitmap that simply isn't big enough when displayed at its intrinsic size, and one that is isn't big enough displayed at its intrinsic size but is stretched to a size that would be adequate if there were enough pixels in the bitmap to start with. This bitmap size problem is one reason often why some people prefer a lower resolution, even though the overall quality is measurably inferior. Another reason why some prefer a lower resolution is poor (resolution dependent) web page design, which typically: 1-leaves input boxes and text areas small in proportion to the amount of text the designer assumed should fit the input area(s) provided 2-often causes text to disappear or overlap other text or images 3-can cause mangled layout leading to difficult to understand content 4-increases frequency of need to apply zoom In summary, _raising_ the _applied/assumed_ DPI to an arbitrary value on a Linux GUI desktop _raises_ text size, _raises_ icon sizes across a limited range, does an arguably reasonable job of preserving window and tools layout when text and icons are mixed, and does nothing that helps compensate for high screen density WRT to such bitmap images as photos, photo-based background images, or most existing (resolution dependent) web page layouts. -- "The wise are known for their understanding, and pleasant words are persuasive." Proverbs 16:21 (New Living Translation) Team OS/2 ** Reg. Linux User #211409 ** a11y rocks! Felix Miata *** http://fm.no-ip.com/ -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org