CTLineGetBoundsWithOptions() uses CTLineBoundsOptions. One of the option is kCTLineBoundsUseOpticalBounds whose doc says:
Pass this option to use optical bounds.
But I don't understand the meaning of optical bounds.
The font designer can specify the optical bounds of a glyph separately from its typographic bounds. In a TrueType font, the opbd table, if present, contains optical bounds.
From WWDC 2012 Session 226: Core Text and Fonts:
Now, as I advance to the next few slides, I want to call your attention in particular to the left and right sides of this rectangle on screen because I’m going to start passing some different options to this API and it’s going to have an effect on either side.
Let’s go ahead and advance now as I invoke use optical bounds. This is a very slight difference here, but you may have noticed that the edges of the box have been pulled in a little bit here. What’s going on here is that optical bounds are very closely related to the typographic bounds, the regular measurement of the line.
But, in this case, the font designer has specified that the way that the font is likely to be perceived by our eyes means that they don’t line up exactly with just the glyph measurements. The optical bounds in this case have been designed to pull in on either of these curly quotes here because the way our eyes see rounded shapes. It’s a bit different than the way we see straight lines, so the font designer has compensated for that by providing us information in the font.
(Find the full session transcript here.)
Microsoft describes it this way:
Aligns glyphs by their apparent left or right extents in horizontal setting, or apparent top or bottom extents in vertical setting, replacing the default behavior of aligning glyphs by their origins. Another name for this behavior would be visual justification. The optical edge of a given glyph is only indirectly related to its advance width or bounding box; this feature provides a means for getting true visual alignment.
Related
I am currently trying to label lines that I draw in my Map (in my iOS app, but I guess it applies to all maps).
So what I currently am doing, I simplify my path so that I get rid of most small curves and then just draw my glyphs along that line. Currently that looks like this:
On some parts of the line that's already ok. If the line is quite straight and the corners aren't too spiky.
But in some parts you can just not read anything... So what are strategies to make that look nicer?
Does anybody know an algorithm or a strategy on how to make my path look like the red line here:
I am happy about any ideas on how to improve my drawing :)
I do it, in my commercial map rendering system, by finding a portion of the line without sharp corners. There is no way to make the label look good if it turns corners of a right angle or greater. If there's no section long enough I abbreviate the label (e.g., Link Road becomes Link Rd), or split it on to two lines. If there's still nowhere to draw the label I don't draw it.
Another thing that's important is to adjust the spacing so that ascenders and descenders don't clash, so you need to look at the bounding box of each adjacent pair of letters as you draw the text and add small amounts of space as necessary.
I don't bother to smooth my lines, as you suggest with your red line. It really doesn't seem to matter, at least with street labelling.
I've imported a vector layer from a psd into paint code v1, I'm trying to create a background image and make it universal.
I can't seem to add a frame around the vector, to complicate matters, I only need a portion, the center, of the layer. (The design is based around a circle, it has lines drawn towards the center of the circle.)
I can’t seem to add a frame to dynamically resize the part I need.
I found this http://www.raywenderlich.com/36341/paintcode-tutorial-dynamic-buttons the part about frame ans groups doesn't help me....
When I add a click frame and drag it around the area I need, it's at the same level as the vector layer. I've also tried adding a group around both, but that doesn't seem to obey the frame size either.
I’ve looked through the tutorials and googled adding a frame, but I can’t seem to achieve what I need.
EDIT
A frame is supposed to be at the same level as the vectors you're working with.
All you do then is set the resize rules of your vectors. There is a little rectangle in the frame's parameters interface with straight arrows and springs that you can modify to fit your wishes.
I think I also remember a checkbox setting to resize only what's inside the frame.
Now I haven't used PaintCode for a while, but if this doesn't help you, there probably is a problem with your vector layer.
I don't know if this information helps.
But if you resizing doesn't work as you expected. Look carefully at the transformation box (the one with the springs attached). When you have put a frame around your object. The middle dot in this box should be blue instead of green. if t's green, you may have a problem with the originating point of your objects and then the resizing may not work as you expected.
I'm trying to get a bounding box for the word "ЛИЛИЯ" in this image, using opencv.
(source: litprom.ru)
I am already experimenting with cv::findContours() and different thresholding alogrithms for couple of days, but can not get any satisfying results.
So, what do I know about this word:
letters are of similar size;
letters' height is in range: 40px — 90px;
word is oriented horizontaly (±5˚);
there is one and only one word on this image;
this word does not intersect image's border (it's fully visible);
different parts of image may have different luminosity;
hotspots (totally white areas) may be present on an image.
English is not my native language, so I'm sorry if the question is not properly explained.
If someone needs more images to answer this question, I have at least a dozen more.
Check out stroke width transform. That is used to text detection.
You can preprocess your image with adaptiveThreshold. You should use a blocksize a little bit bigger than your biggest character. I tried on your image with 91 and it gave good results. Then you can use FindContours and filter the blobs/contours using their height. Note that the letters will still be connected one to another so you cannot really filter using the width.
I am rendering some italic text using ID3DXFont::DrawText. Although i specify DT_NOCLIP and the rectangle is big enough, usually, but not only, last character of the text isn't show completely, but it is rather cut from its right side.
What can be the reason and how can I fix it? Any ideas?
This is a common malfunction in the ID3DFont class, and it is not solventable (as I know of). It doesn't calculate real rectangle areas when characters have different character width and render width, mainly when calculating total rectangle area of a complete sentence.
Also rare fonts (that have render rectangles the overlap other characters) will be cut for sure too.
Other malfunctions include kerning pairs, as it simply doesn't care about them. The classic AV example will be rendered as if it had a white space in the middle.
Because of this, the best solution is to avoid ID3DFont, and code yourself a text renderer, or use other alternatives like DirectWrite.
http://msdn.microsoft.com/en-us/library/dd368038%28v=vs.85%29.aspx
It could be an aliasing issue? Perhaps the rectangle isn't actually big enough?
You should post some code and a screenshot of the problem though...
Can anyone share a sample code to draw a non-rectangular part of a picture in delphi canvas?
You're looking for GDI paths. Start here, which explains what paths are in this context, and provides links on the left to explain the functionality available with them.
Google can turn up lots of examples of using paths in Delphi. If you can't find them, post a comment back here and I'll see what I can turn up for you.
Your question is pretty vague. But I suspect what you are looking for is clipping regions. Read up on them. Set the clipping region on the target device to the shape you want, and then draw the image onto the device. Only the part of the image that would be within the clipping region will be drawn.
Canvas.Ellipse(0, 0, 10, 20); // not a rectangle
I use so called runlists for this feature (generalized shapes and blitting them). I've seen them called warplists too. A shape is encoded as a runlist by defining it as a set of horizontal lines, and each line is two integer values (skip n pixels,copy n pixels).
This means you can draw entire lines, leaving you with only "height" draw operations.
So a rectangle is defined (the first "skip" pixels from top level corner to the left corner (xorg,yorg). The rectangle is width_rect wide, and width_pixels goes a line further. width_pixels can be wider than the width of the picture (alignment bytes)
(yorg*width_pixels+xorg , width_rect),
(width_pixels-width_rect , width_rect),
(width_pixels-width_rect , width_rect),
(width_pixels-width_rect , width_rect),
..
..
This way you can make your drawing routines pretty generic, and for simple, regular shapes (rects, circles) it takes only minor math to precalculate these lists. It simplified my shape handling enormously.
However I draw directly to bitmaps, not to canvasses, so I can't help with that part. A primitive that efficiently draws a row, and a way to extract a row from a graphic should be enough.