[Cuis-dev] Big News! Cuis is now Unicode and Vector Graphics

[Juan Vuletich]

Hi Mariano,

Thanks for the samples and the details on your screen. Now I can tell 
what you see.

Other Text Rasterization Engines, such as FreeType, CoreText and 
ClearType do auto-hinting of glyphs. This aligns glyph features to 
integer pixel coordinates at the expense of correct geometry. 
VectorEnginePlugin doesn't. It rasterizes glyphs just like any other 
vector graphics, respecting the true geometry of glyphs.

This is only noticeable in horizontal lines, when they want to cover 
half a pixel or so.

If you disable glyph caching, or (even slightly) zoom windows, then not 
even the position of glyphs is aligned to integer pixels, giving a more 
correct layout of text, making each instance of the same character be 
drawn differently. You can see this if you capture a screen and zoom the 
pixels to make them larger.

This is a rather fundamental decision on how VectorEngine works. It 
doesn't "draw pixels", but applies a low pass filter and then samples a 
continuous shape.

The older StrikeFonts were rendered with FreeType, and then captured as 
Bitmaps.

Thanks,



On 10/30/2022 10:28 AM, Mariano Montone via Cuis-dev wrote:
> El 29/10/22 a las 21:01, Juan Vuletich escribió:
>> Hi Mariano,
>>
>> On 10/29/2022 7:53 AM, Mariano Montone via Cuis-dev wrote:
>>> A thing I would like to adjust if it were possible, is that I feel 
>>> like the font rendering loses some sharpness with VG; some fonts 
>>> more than others, and some sizes more than others.
>>
>> You can tweak 
>> VectorEngineWithPluginSubPixel>>#defaultAntiAliasingWidth and then 
>> evaluate `TrueTypeFont allInstancesDo: [ :f | f releaseCachedState 
>> ].`, to try different parameters for the antialiasing filter.
> Ah, apologies to Gerald, I didn't see that part when he pointed it to me.
>>
>> Still, I'm curious. Can you post a Display using 
>> HybridCanvas/VectorCanvas and another using BitBltCanvas? Best if you 
>> can include some fonts/sizes you feel are sharp enough, and others 
>> that aren't. If file sizes are too big for the list (I believe it is 
>> 500kb once encoded in MIME64), please send them to me privately.
> I'm inserting some images below. Look at the equality symbol for 
> example. I think the problem is that the greying of the font is too 
> much and makes the font blurry. But my comparison is probably unfair, 
> since I'm using the DejaVuBitmap font for the Bitmap case, with 
> doesn't use the greying, or too little; but that's an example of what 
> I mean "sharp".
>>
>> One question: What Display resolution do you use? Size of screen? 
>> Does the `Display size` in Cuis match the OS and physical screen 
>> resolution? (this is rarely the case on MacOS, unfortunately).
>
> I'm on Linux with screen size of 1366x768. Cuis Display is 1360x713.
>
>>
>> Finally, a screen capture of an editor in your host OS with some text 
>> that looks sharp to your eyes would be helpful.
>
> Bitmap Cuis (DejaVuBitmap) (sharp):
>
> Vector (DejaVuSans) (not sharp):
>
> Host OS app:
>
>
> I feel like the Host OS is using less greying around the fonts than 
> Cuis and that makes it sharper.
>
>
> Thanks,
>
>     Mariano
>
>
>


-- 
Juan Vuletich
cuis.st
github.com/jvuletich
researchgate.net/profile/Juan-Vuletich
independent.academia.edu/JuanVuletich
patents.justia.com/inventor/juan-manuel-vuletich
linkedin.com/in/juan-vuletich-75611b3
twitter.com/JuanVuletich

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