I have a problem which I hope you can help me solving.
I'm creating a program using Xamarin.Mac (C# for Mac) and I need to draw a DNA sequence (ATGC and so on). However, I need to know the exact position of each character so I can draw several other objects which should be aligned with the characters in DNA sequence.
Screenshot of the Windows version of my app which illustrates the behavior I'm looking for:
Currently I'm looking to use the CALayer drawing method, which appears to be fast enough to render 12 lines of 70 characters in less than 50 ms. CALayers are not fast enough to render 1000 CATextLayers with one (A/T/G/C) character each, so (I think) I need to render them as lines with specific spacing. This means that I need to have exactly 10 (example) pixels between the center of each character.
However, I cannot find a way to do this.
The NSAttributedString Kerning seems be added to an unknown existing tracking (or spacing) of the font, and thus may be used with monospace fonts but still results in an unknown actual spacing.
I CAN get around the issue by trial and error until the letter spacing appears to match the desired spacing, but I'm not very confident in robustness of this method across different devices (screen resolutions). This requires that I use a monospace font, which is okay, but not optimal.
Is it possible to have specific character spacing using a single CATextLayer and what are my options if not? is it possible to have 1000 characters drawn individually without a huge performance impact?
Thank you.
