How can we render the unicode string? What would be a proper algorithm?
\nx = start_x\ny = start_y\nwith all glyph elements ge in the vector:\n print unicode ge.g at x,y\n x = x + ge.ax\n y = y + ge.ay\nAt least the above algorithm does not lead to a proper result. It looks more like this (first row):
\n
Also the scaling of ax and ay is not clear (in the screenshot ax/ay are divided by 4)
\nEdit: Fixed algorithm
","upvoteCount":1,"answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"You are spot on.
\nI don't know your system. You can connect back to the Unicode via the cluster cl member of the json. See:
https://harfbuzz.github.io/clusters.html
","upvoteCount":0,"url":"https://github.com/harfbuzz/harfbuzz/discussions/5362#discussioncomment-13455236"}}}
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Thanks for providing hb-shape. It looks like a solution for our rendering problems in u8g2, but we are wondering how to use the JSON output of hb-shape. Also the manual at https://harfbuzz.github.io/utilities.html#utilities-command-line-hbshape does not really describe the meaning of the JSON result. The question is: How would a render algorithm look like, that makes use of the JSON output of hb-shape. Example (from olikraus/u8g2#2656) Goal is to render "नमस्ते" With [
{"g":2345,"cl":0,"dx":0,"dy":0,"ax":64,"ay":0,"xb":0,"yb":44,"w":64,"h":-40},
{"g":2351,"cl":1,"dx":0,"dy":0,"ax":64,"ay":0,"xb":0,"yb":44,"w":64,"h":-40},
{"g":2361,"cl":2,"dx":0,"dy":0,"ax":64,"ay":0,"xb":0,"yb":44,"w":64,"h":-40},
{"g":2382,"cl":2,"dx":0,"dy":0,"ax":0,"ay":0,"xb":-28,"yb":4,"w":16,"h":-12},
{"g":2341,"cl":4,"dx":0,"dy":0,"ax":64,"ay":0,"xb":0,"yb":44,"w":64,"h":-40},
{"g":2376,"cl":4,"dx":0,"dy":0,"ax":0,"ay":0,"xb":-52,"yb":56,"w":24,"h":-12}
]How can we render the unicode string? What would be a proper algorithm? At least the above algorithm does not lead to a proper result. It looks more like this (first row): Also the scaling of ax and ay is not clear (in the screenshot ax/ay are divided by 4) Edit: Fixed algorithm |
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Replies: 1 comment 22 replies
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Accumulate ax and ay as you are, but draw each glyph at x+ge.dx and y+ge.dy. You might need to set font size on hb-shape. |
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Looking a little bit forward into the JSON structure: The "g" member does not seem to be the unicode value, right? The unicode of uppercase A should be 65 instead (so 36 probably is the internal glyph index) |
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At least hb-view works as expected :-) |
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So, as a summary so far: The value of the "g" member of the generated JSON is NOT the unicode, but instead it is the glyph index within the font. So that had been a misunderstanding on my side. However it would be great to have the unicode number (It may not always exist however) |
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You are spot on. I don't know your system. You can connect back to the Unicode via the cluster |
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Ah, nice, thanks for the link. This answers my questions. |
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Based on the above discussion, my algorithm now works: It produces the expected result: However, assumptions are:
So... not all assumtions are true in general, so the above algorithm can't be applied in general (but it seems to be good enough for my application). Thanks for the support... I learned a lot! |
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The assumption about |
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Thanks again for the feedback. True, even cl_offset is an assumption, however so far it works for my examples. |
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You are spot on.
I don't know your system. You can connect back to the Unicode via the cluster
clmember of the json. See:https://harfbuzz.github.io/clusters.html