Spriteful TErminal GrAphics Protocol: Difference between revisions

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Support for 6-bit greyscale pixels with a bit of alpha channel, transmitted as bias-32 bytes in row-major order, is <b>mandatory</b>. If 64 levels of greyscale are not available, at a minimum, the 6-bit range must be partitioned into a non-empty range mapping to black, and a non-empty range mapping to white. Each byte contains a value between 32 (0x20) and 96 (0x60), inclusive. This value is equal to 32 + the greyscale value for values less than 96, or transparent if equal to 96. This leaves 31 legal 7-bit-clean values on either side (remember, ESC is prohibited).

Alternatively, we could use bias-31 bytes. This leaves 30 legal 7BC values on the low end, and 32 on the high end. We lose the property that all defined values are printable if we do this, along with some pleasing (but in the end, meaningless) bit-pattern properties.

*Alternatively, we could use bias-31 bytes. This leaves 30 legal 7BC values on the low end, and 32 on the high end. We lose the property that all defined values are printable if we do this, along with some pleasing (but in the end, meaningless) bit-pattern properties.

Alternatively, we could provide a 7-bit greyscale. We lose the property of being seven-bit-clean if we do so.

*Alternatively, we could provide a 7-bit greyscale. We lose the property of being seven-bit-clean if we do so.

Using a unit smaller than a byte would require defining a padding mechanism at row's end, and complicates calculations for necessary length.

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 Support for 6-bit greyscale pixels with a bit of alpha channel, transmitted as bias-32 bytes in row-major order, is <b>mandatory</b>. If 64 levels of greyscale are not available, at a minimum, the 6-bit range must be partitioned into a non-empty range mapping to black, and a non-empty range mapping to white. Each byte contains a value between 32 (0x20) and 96 (0x60), inclusive. This value is equal to 32 + the greyscale value for values less than 96, or transparent if equal to 96. This leaves 31 legal 7-bit-clean values on either side (remember, ESC is prohibited).
-Alternatively, we could use bias-31 bytes. This leaves 30 legal 7BC values on the low end, and 32 on the high end. We lose the property that all defined values are printable if we do this, along with some pleasing (but in the end, meaningless) bit-pattern properties.
+*Alternatively, we could use bias-31 bytes. This leaves 30 legal 7BC values on the low end, and 32 on the high end. We lose the property that all defined values are printable if we do this, along with some pleasing (but in the end, meaningless) bit-pattern properties.
-Alternatively, we could provide a 7-bit greyscale. We lose the property of being seven-bit-clean if we do so.
+*Alternatively, we could provide a 7-bit greyscale. We lose the property of being seven-bit-clean if we do so.
 Using a unit smaller than a byte would require defining a padding mechanism at row's end, and complicates calculations for necessary length.

Spriteful TErminal GrAphics Protocol: Difference between revisions

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