linear_scale_range.json

{
    "id": "linear_scale_range",
    "summary": "Linear transformation between two ranges",
    "description": "Performs a linear transformation between the input and output range.\n\nThe underlying formula is: `((x - inputMin) / (inputMax - inputMin)) * (outputMax - outputMin) + outputMin`.\n\nPotential use case include\n\n* scaling values to the 8-bit range (0 - 255) often used for numeric representation of values in one of the channels of the [RGB colour model](https://en.wikipedia.org/wiki/RGB_color_model#Numeric_representations) or\n* calculating percentages (0 - 100).\n\nThe no-data value `null` is passed through and therefore gets propagated.",
    "categories": [
        "math"
    ],
    "parameter_order": ["x", "inputMin", "inputMax", "outputMin", "outputMax"],
    "parameters": {
        "x": {
            "description": "A number to transform.",
            "schema": {
                "type": [
                    "number",
                    "null"
                ]
            },
            "required": true
        },
        "inputMin": {
            "description": "Minimum value the input can obtain.",
            "schema": {
                "type": "number"
            },
            "required": true
        },
        "inputMax": {
            "description": "Maximum value the input can obtain.",
            "schema": {
                "type": "number"
            },
            "required": true
        },
        "outputMin": {
            "description": "Minimum value of the desired output range.",
            "schema": {
                "type": "number",
                "default": 0
            }
        },
        "outputMax": {
            "description": "Maximum value of the desired output range.",
            "schema": {
                "type": "number",
                "default": 1
            }
        }
    },
    "returns": {
        "description": "The transformed number.",
        "schema": {
            "type": [
                "number",
                "null"
            ]
        }
    },
    "examples": [
        {
            "arguments": {
                "x": 0.3,
                "inputMin": -1,
                "inputMax": 1,
                "outputMin": 0,
                "outputMax": 255
            },
            "returns": 165.75
        },
        {
            "arguments": {
                "x": 25.5,
                "inputMin": 0,
                "inputMax": 255
            },
            "returns": 0.1
        },
        {
            "arguments": {
                "x": null,
                "inputMin": 0,
                "inputMax": 100
            },
            "returns": null
        }
    ]
}