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kf-2.15.4 released

Another 2 months later and kf-2.15.4 is ready. Kalles Fraktaler 2 + is fast deep zooming Free Software for fractal graphics (Mandelbrot, Burning Ship, etc). Full change log:

kf-2.15.4 (2021-07-22)

  • new: rewritten GUI for window size / image size (by popular request)
  • new: “imaginary axis points up” option in the transformation dialog (requested by saka and others, makes complex plane comply with maths conventions)
  • new: Hidden Mandelbrot formula (thanks to FractalAlex, Bruce Dawson)
  • new: Hidden Mandelbrot a la Cos formula (thanks to 3Dickulus)
    • set Factor A real and imaginary parts to control shape (e.g. 1+1i)
  • new: Polarbrot formula, for p = 2, 3, 4 (thanks to gerrit)
    • set Factor A real part to control power a
    • fractional and/or negative power a is possible
    • known issue: need to set Bailout escape radius very high (but not so high that derivatives overflow: try 1e10 or so)
    • known issue: for positive a, reference at 0 fails (blank image) (workaround: offset the center very slightly in the Location dialog)
    • known issue: for negative a, blank image (workaround: set Formula seeds non-zero (1e-300); this will reduce accuracy for deeper zooms)
    • known issue: seams with numeric differences DE (analytic DE is ok)
    • known issue: Newton zooming is not functional yet
    • known issue: auto-skew is not functional yet
  • new: convert between built-in formulas and hybrid formulas (when possible) with new buttons in the Formula dialog
  • new: option Ignore Hybrids in the Formula dialog to list only the built-in formulas that don’t have hybrid equivalents
  • new: optimized some built-in formulas using common subexpression elimination (6%-58% faster perturbation calculations)
    • Burning Ship power 2, 3, 4, 5
    • Buffalo power 2, 3, 4
  • new: optimized some hybrid OpenCL perturbation calculations
  • fix: Hybrid operator multiplication works with OpenCL
  • fix: Omnibrot works with OpenCL
  • fix: Mandelbrot power 4 and above with derivatives works with OpenCL
  • fix: formulas 52, 53, 69, 70, 71 now work with OpenCL
  • fix: formulas 4 (power 3), 20, 23-26, 42-50 now have correct derivatives for analytic DE
  • fix: renamed some formulas (Abs General Quadratic Plus/Minus, Omnibrot) (suggested by gerrit)
  • fix: Zoom Amount spinner in Transformation dialog works live
  • fix: Transformation dialog Zoom Amount sign inversion
  • fix: right mouse button drag in Transformation dialog stretches in a more intuitive way
  • fix: Transformation dialog displays/edits total transformation instead of difference from last set transformation
  • fix: Newton zoom dialog (atom domain) size of period <=1 is set to 1
  • fix: OpenCL error dialog no longer appears and disappears again instantly
  • internal: formula build system refactored for parallel building and much faster incremental builds
  • internal: include structure rationalized for faster builds
  • internal: use intermediate ar archives for linking many object files
  • internal: formula preprocessor supports temporary variables (can be used for common subexpression elimination)
  • upgrade to gsl-2.7
  • upgrade to openexr-2.5.7

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