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Belgian Amiga Club - ADF Collection
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BS1 part 60
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Imagemaster d4.adf
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mfa_hlp
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1993-08-30
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\ApAssist
\: - This is the Quick Help for the file i/o amiga render mode panel -
\: ---------------------------------------------------------------------
\: Written by David E. Patterson
\: ---------------------------------------------------------------------
\font topaz.font 8
\tc 1
\wr
\lj
\dd "imh_descriptor"
\index "hlp_index/index"
\toc "hlp_toc/toc"
\help "aa_help/help
\node "mfa_modereg"
\title "Register"
\next "mfa_xtrahalfbrite"
\prev ""
Register mode can be described as a mode where each pixel in the image is
described by a single color register. In the Amigas which have the \{ \ts i
AGA \} chipset, these color registers are 24-bits accurate. In older model
Amigas, the color registers are only 12-bits. The number of color registers
available depends upon the setting of the "Bit Depth" options; you may have
from 2 to 256 colors in a register mode image.
\endnode
\node "mfa_xtrahalfbrite"
\title "Extra Half Brite"
\next "mfa_ham"
\prev "mfa_modereg"
Extra Half Brite is a mode that was developed for the older Amigas in order
to add extra colors without having to add more color registers. Here, the
image is always 6 bitplanes, providing 64 possible values for each pixel. If
the pixel contains a value from zero to 31, then the color produced is equal
to that specified in color registers zero to 31. However, if the pixel
contains a value from 32 to 63, then the color produced is that of a color
register chosen from the first 32, but only half as bright - hence the name
"half brite". The register from the first 32 is chosen by dividing the value
(which is 32-63), by two. For instance, if the pixel contains the value 60,
color register 30 is used, except it will be 1/2 as bright as the color in
register 30. There is also a subtle catch here; a color register that
contains brightness values in any combination of its R, G and B components
that are odd, such as 7, 9 and 11, cannot be changed to exactly 1/2 its
original brightness; this is because (for instance) 7 / 2 = 3.5, and the
Amiga cannot generate a color that is accurate to .5 of a brightness step.
This makes the choosing of half brite colors more challenging, since these
small errors must be taken into account when generating an image. If you are
generating images for AGA based machines, we suggest that you never use Half-
Brite; use 64 register colors instead. It costs exactly the same amount of
memory, processor time and so on, yet it gives you a much more flexible way
to create an image. Remember also that Half-Brite mode is only available in
Low-Res on non-AGA machines.
\endnode
\node "mfa_ham"
\title "HAM"
\next "mfa_lowres"
\prev "mfa_xtrahalfbrite"
There are two Amiga HAM modes. The first is available in all machines; the
second is only available in machines which utilize the AGA chipset. HAM uses
a technique whereby a pixel's color may be obtained either from one of a
group of color registers, or by modifying either the red, green or blue value
of the previous pixel. 6-Bit HAM mode, which is available on all machines,
allows color selection from any one of 16 color registers, or modification of
4-bits (16 levels) of color from the previous horizontal pixel. 8-Bit HAM
mode (which was first introduced to the Amiga marketplace by \{ \ts b Black
Belt Systems\} ) allows color selection from any one of 64 color
registers, or modification of 6-bit (64 levels) of color from the previous
horizontal pixel.
\endnode
\node "mfa_lowres"
\title "Low Resolution"
\next "mfa_highres"
\prev "mfa_ham"
This button, when selected, will render the output in low resolution.
\endnode
\node "mfa_highres"
\title "High Resolution"
\next "mfa_super72"
\prev "mfa_lowres"
This button, when selected, will render the output in high resolution.
\endnode
\node "mfa_super72"
\title "Super 72 800x600"
\next "mfa_superhigh"
\prev "mfa_highres"
This button, when selected, will render the output in Super 72 resolution
(800x600).
\endnode
\node "mfa_superhigh"
\title "Super High Resolution"
\next "mfa_1bp2col"
\prev "mfa_super72"
This button, when selected, will render the output in super high resolution.
\endnode
\node "mfa_1bp2col"
\title "1 Bit Plane, 2 Colors "
\next "mfa_2bp4col"
\prev "mfa_superhigh"
This will render the output using only 1 bit plane, and 2 colors. This is
only available if the \{ \ts i \tc 10 Register \} button is selected.
\endnode
\node "mfa_2bp4col"
\title "2 Bit Planes, 4 Colors"
\next "mfa_3bp8col"
\prev "mfa_1bp2col"
This will render the output using 2 bit planes and 4 colors. This is only
available if the \{ \ts i \tc 10 Register \} button is selected.
\endnode
\node "mfa_3bp8col"
\title "3 Bit Planes, 8 Colors"
\next "mfa_4bp16col"
\prev "mfa_2bp4col"
This will render the output using 4 bit planes and 8 colors. This is only
available if the \{ \ts i \tc 10 Register \} button is selected.
\endnode
\node "mfa_4bp16col"
\title "4 Bit Planes, 16 Colors"
\next "mfa_5bp32col"
\prev "mfa_3bp8col"
This will render the output using 4 bit planes and 16 colors. This is only
available if the \{ \ts i \tc 10 Register \} button is selected.
\endnode
\node "mfa_5bp32col"
\title "5 Bit Planes, 32 Colors"
\next "mfa_6bp64col"
\prev "mfa_4bp16col"
This will render the output using 5 bit planes and 32 colors. This is only
available if the \{ \ts i \tc 10 Register \} button is selected.
\endnode
\node "mfa_6bp64col"
\title "6 Bit Planes, 64 Colors"
\next "mfa_7bp128col"
\prev "mfa_5bp32col"
This will render the output using 6 bit planes and 64 colors. This is
available for all render modes.
\endnode
\node "mfa_7bp128col"
\title "7 Bit Planes, 128 Colors"
\next "mfa_8bp256col"
\prev "mfa_6bp64col"
This will render the output using 7 bit planes and 128 colors. This is only
available if the \{ \ts i \tc 10 Register \} button is selected.
\endnode
\node "mfa_8bp256col"
\title "8 Bit Planes, 256 Colors"
\next "mfa_12b4096col"
\prev "mfa_7bp128col"
This will render the output using 4 bit planes and 16 colors. This is only
available if the \{ \ts i \tc 10 Register \} or \{ \ts i \tc 10 Ham \} button
is selected.
\endnode
\node "mfa_12b4096col"
\title "12 Bit - 4096 Colors - Displayable"
\next "mfa_24b155mcol"
\prev "mfa_8bp256col"
This will render the image using 12 bits and 4,096 colors. It is a
displayable render.
\endnode
\node "mfa_24b155mcol"
\title "24 Bits - 16.5m Colors - Non-Displayable"
\next "mfa_interlace"
\prev "mfa_12b4096col"
This will render the image using 24 bits and 16.5 million colors. It is not
a displayable render.
\endnode
\node "mfa_interlace"
\title "InterLace"
\next "mfa_noninterlace"
\prev "mfa_24b155mcol"
This will interlace the rendered output.
\endnode
\node "mfa_noninterlace"
\title "Non-InterLace "
\next ""
\prev "mfa_interlace"
This will use the non-interlace mode for the rendered output.
\endnode