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70 lines
2.6 KiB
Markdown
70 lines
2.6 KiB
Markdown
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[](https://github.com/marketplace/actions/arduino_ci)
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[](https://github.com/RobTillaart/map2colour/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/map2colour/actions/workflows/jsoncheck.yml)
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[](https://github.com/RobTillaart/map2colour/blob/master/LICENSE)
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[](https://github.com/RobTillaart/map2colour/releases)
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# map2colour
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Arduino library for mapping a float to colour spectrum
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## Description
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The map2colour library is used to make map a reading from a sensor, e.g. temperature or pressure,
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to a colour in the RGB spectrum.
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The initial release uses 7 floats values that describe the range being mapped.
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These are passed to the library with **begin()**.
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These 7 floats must be in ascending order and are mapped upon the following colour array.
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```cpp
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uint32_t colours[] =
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{
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// BLACK RED YELLOW GREEN ?? BLUE WHITE
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0x00000000, 0x00FF0000, 0x00FFFF00, 0x0000FF00, 0x0000FFFF, 0x000000FF, 0x00FFFFFF
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}
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```
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New values will be linear interpolated between the two points when needed.
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Assume you initialize a float array
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```cpp
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float tempArray[] = { -10, -10, 5, 15, 30, 60, 125 }; // note the double -10
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```
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A temperature of 0°C will be mapped between the 2nd and 3rd element so somewhere
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between RED and YELLOW.
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A temperature between 60°C and 125°C will be mapped between BLUE and WHITE.
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This first version is to get hands on experience, a later version should
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support user defined colour maps.
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## Interface
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- **map2colour()** constructor.
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- **bool begin(float \* ar)** load the array with 7 boundaries.
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- **uint32_t map2RGB(float value)** returns RGB colour packed in an uint32_t. **0x00RRGGBB**
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## Operation
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See examples.
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## Future
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- update documentation
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**0.2.0** thoughts
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- make the colour map user defined - like multi-map
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- between BLACK and a single colour. - intensity
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- between a number of colours e.g. RED YELLOW GREEN or GREEN YELLOW RED
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- fixed number of points is flex enough
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- example with double entries
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- temp -10, 5, 10, 30, 35, 60, 120
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- Red yellow black black yellow red red
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- middle area 10..30 has no colour.
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