Fonts have natural margins that vary widely. A decorative or cursive font may have ascenders and descenders much higher and lower than a book typeface. That means the leading between the lines needs to be larger. I use display font for the labels for my forms, called Verdana has an automatic 16 point margin at 14 point font size, even though there is nothing about the font itself requiring it! It's just how the font is done.
Bob S > On Feb 3, 2018, at 09:12 , Ralph DiMola via use-livecode > <use-livecode@lists.runrev.com> wrote: > > David, > > Nice.... I've been wrestling with this. I am going to see how your > observations translate into mobile. I'm going to apply your of findings to my > app and see if I get better results than I get now. There have been a few > threads in the past few years addressing vertically centering text in a > field. None of them seem to address all font size cases. This 6px thingy > might explain a lot! > > Thanks again for all your work. > > Ralph DiMola > IT Director > Evergreen Information Services > rdim...@evergreeninfo.net > > -----Original Message----- > From: use-livecode [mailto:use-livecode-boun...@lists.runrev.com] On Behalf > Of David Epstein via use-livecode > Sent: Friday, February 02, 2018 9:38 PM > To: use-livecode@lists.runrev.com > Cc: David Epstein > Subject: Re: FormattedHeight of a field and its contents > > Thanks for the responses on this. I used Bernd’s tool and did some more > tests, and found some things that may be helpful to others. > > While the left and right margins of a field are meant literally (a 5 pixel > left margin leaves 5 white pixels to the left of the text), the top margin is > more complicated, no doubt owing to the variety of textHeights that need to > be accommodated. For example, a margin of "0" will often clip the top of the > text--as if "0" meant a "negative margin". > > 6 seems to be a magic default value for a field's top margin, which avoids > clipping the content. With horizontal gridlines visible, a 6 pixel buffer > makes the top row the same height as the other rows. And with a 6 pixel > buffer the formattedHeight of the field will exactly match the > formattedHeight of the field's content (although a non-zero borderwidth or a > horizontal scrollbar changes this). > > Thus--what I wondered about in my original post--with a margin less than 6 > the formattedHeight of the field is less than the formattedHeight of the > content; the content is in effect clipped. At smaller textHeights this will > be visible, while at larger textHeights only white space above the characters > is clipped. > > I was trying to answer two questions, and I think I'm pretty close. > > 1. How do I make sure that the field's contents are all visible if I set the > field's height to the formattedHeight? Answer: Set the top and bottom > margins to 6. For the left and right margins, even 1 pixel should be enough > to keep everything visible. > > 2. What margins will provide a symmetrical look for a text box? > A top margin of 6 doesn’t look like a 6 pixel margin; how it looks depends on > the textHeight. I estimate that its apparent height is one fourth of the > effective textHeight, and I use this to size the other margins in the > “tightMargins” handler below. > While the top margin of 6 looks good with horizontal gridlines, without them > (and especially if you show a text baseline) it looks too small compared to > the space between subsequent lines. To match that larger space, in effect > doubling the apparent top margin, add one third of the effective textHeight. > See “niceMargins” handler below. > > Example of usage: > set the margins of fld 1 to the niceMargins of fld 1 set the height of fld 1 > to the formattedHeight of fld 1 > > getProp niceMargins > put the effective textHeight of the target into t > put round(t*7/12) into m1 > put round(t/3) into m2 > return m1,6+m2,m1,m1 > end niceMargins > > getProp tightMargins > put round(.25*the effective textHeight of the target) into m > return m,6,m,max(6,m) > end tightMargins > > Improvements to these are welcomed. > > David Epstein > > > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription > preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode > > > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription > preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
