forked from KolibriOS/kolibrios
75 lines
2.3 KiB
Plaintext
75 lines
2.3 KiB
Plaintext
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=========================
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Scale2x, Scale3x, Scale4x
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=========================
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Scale2x, Scale3x and Scale4x are real-time graphics effects
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able to increase the size of small bitmaps guessing the
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missing pixels without blurring the images.
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They were originally developed for the AdvanceMAME project
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in the year 2001 to improve the quality of old games running
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at low video resolutions.
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The specification of the algorithm and more details are at :
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http://scale2x.sourceforge.net
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This package contains some implementations of the effects
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in C and MMX Pentium assembler, and command line tools to
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convert manually .PNG images.
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1 IMPLEMENTATION
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================
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The files scale2x.c and scale3x.c are the fast C and MMX
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implementations of the effects.
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The files scalebit.c and scalebit.h are the fast C implementations
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of the effects ready to be applied to a generic bitmap.
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Note that the implementation of the Scale4x effect is not
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obvious without using a big intermediate buffer.
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The files scalerx.c is a simple command line processors,
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which uses the reference implementation of the effects.
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The files scalex.c is another simple command line processors,
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which uses the fast implementation of the effects.
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2 TOOLS
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=======
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The command line tools "scalerx" and "scalex" read a .PNG file
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and write another .PNG file with the effect applied.
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The syntax of the programs is :
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scalerx [-k N] [-w] FROM.png TO.png
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scalex [-k N] FROM.png TO.png
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The option -k can be used to select the scale factor.
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The option -w can be used to scale textures with a wraparound effect.
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To compile the command line tool you need the libz and libpng
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libraries.
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3 EXAMPLES
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==========
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The directory example/ contains some examples of the effects applyed
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to a generic image and to a test image.
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The suffix of the images means :
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1 - Original image.
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2 - Scale2x effect.
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3 - Scale3x effect.
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4 - Scale4x effect.
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1x - Scaled normally 12 times.
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2x - Scale2x effect and scaled normally up to 12 times.
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3x - Scale3x effect and scaled normally up to 12 times.
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4x - Scale4x effect and scaled normally up to 12 times.
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The `x' images have the same final size and can be used to compare
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pixel by pixel the result of the effects.
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