@deck.gl/layers/src/text-layer/text-background-layer/text-background-layer.ts

deck.gl core layers

// deck.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

import {Layer, project32, picking, UNIT} from '@deck.gl/core';
import {Geometry} from '@luma.gl/engine';
import {Model} from '@luma.gl/engine';

import {TextBackgroundProps, textBackgroundUniforms} from './text-background-layer-uniforms';
import vs from './text-background-layer-vertex.glsl';
import fs from './text-background-layer-fragment.glsl';

import type {
  LayerProps,
  LayerDataSource,
  Accessor,
  Unit,
  Position,
  Color,
  UpdateParameters,
  DefaultProps
} from '@deck.gl/core';

type _TextBackgroundLayerProps<DataT> = {
  data: LayerDataSource<DataT>;
  billboard?: boolean;
  sizeScale?: number;
  sizeUnits?: Unit;
  sizeMinPixels?: number;
  sizeMaxPixels?: number;

  borderRadius?: number | [number, number, number, number];
  padding?: [number, number] | [number, number, number, number];

  getPosition?: Accessor<DataT, Position>;
  getSize?: Accessor<DataT, number>;
  getAngle?: Accessor<DataT, number>;
  getPixelOffset?: Accessor<DataT, [number, number]>;
  getBoundingRect?: Accessor<DataT, [number, number, number, number]>;
  getFillColor?: Accessor<DataT, Color>;
  getLineColor?: Accessor<DataT, Color>;
  getLineWidth?: Accessor<DataT, number>;
};

export type TextBackgroundLayerProps<DataT = unknown> = _TextBackgroundLayerProps<DataT> &
  LayerProps;

const defaultProps: DefaultProps<TextBackgroundLayerProps> = {
  billboard: true,
  sizeScale: 1,
  sizeUnits: 'pixels',
  sizeMinPixels: 0,
  sizeMaxPixels: Number.MAX_SAFE_INTEGER,

  borderRadius: {type: 'object', value: 0},
  padding: {type: 'array', value: [0, 0, 0, 0]},

  getPosition: {type: 'accessor', value: (x: any) => x.position},
  getSize: {type: 'accessor', value: 1},
  getAngle: {type: 'accessor', value: 0},
  getPixelOffset: {type: 'accessor', value: [0, 0]},
  getBoundingRect: {type: 'accessor', value: [0, 0, 0, 0]},
  getFillColor: {type: 'accessor', value: [0, 0, 0, 255]},
  getLineColor: {type: 'accessor', value: [0, 0, 0, 255]},
  getLineWidth: {type: 'accessor', value: 1}
};

export default class TextBackgroundLayer<DataT = any, ExtraPropsT extends {} = {}> extends Layer<
  ExtraPropsT & Required<_TextBackgroundLayerProps<DataT>>
> {
  static defaultProps = defaultProps;
  static layerName = 'TextBackgroundLayer';

  state!: {
    model?: Model;
  };

  getShaders() {
    return super.getShaders({vs, fs, modules: [project32, picking, textBackgroundUniforms]});
  }

  initializeState() {
    this.getAttributeManager()!.addInstanced({
      instancePositions: {
        size: 3,
        type: 'float64',
        fp64: this.use64bitPositions(),
        transition: true,
        accessor: 'getPosition'
      },
      instanceSizes: {
        size: 1,
        transition: true,
        accessor: 'getSize',
        defaultValue: 1
      },
      instanceAngles: {
        size: 1,
        transition: true,
        accessor: 'getAngle'
      },
      instanceRects: {
        size: 4,
        accessor: 'getBoundingRect'
      },
      instancePixelOffsets: {
        size: 2,
        transition: true,
        accessor: 'getPixelOffset'
      },
      instanceFillColors: {
        size: 4,
        transition: true,
        type: 'unorm8',
        accessor: 'getFillColor',
        defaultValue: [0, 0, 0, 255]
      },
      instanceLineColors: {
        size: 4,
        transition: true,
        type: 'unorm8',
        accessor: 'getLineColor',
        defaultValue: [0, 0, 0, 255]
      },
      instanceLineWidths: {
        size: 1,
        transition: true,
        accessor: 'getLineWidth',
        defaultValue: 1
      }
    });
  }

  updateState(params: UpdateParameters<this>) {
    super.updateState(params);
    const {changeFlags} = params;
    if (changeFlags.extensionsChanged) {
      this.state.model?.destroy();
      this.state.model = this._getModel();
      this.getAttributeManager()!.invalidateAll();
    }
  }

  draw({uniforms}) {
    const {billboard, sizeScale, sizeUnits, sizeMinPixels, sizeMaxPixels, getLineWidth} =
      this.props;
    let {padding, borderRadius} = this.props;

    if (padding.length < 4) {
      padding = [padding[0], padding[1], padding[0], padding[1]];
    }

    if (!Array.isArray(borderRadius)) {
      borderRadius = [borderRadius, borderRadius, borderRadius, borderRadius];
    }

    const model = this.state.model!;
    const textBackgroundProps: TextBackgroundProps = {
      billboard,
      stroked: Boolean(getLineWidth),
      borderRadius,
      padding: padding as [number, number, number, number],
      sizeUnits: UNIT[sizeUnits],
      sizeScale,
      sizeMinPixels,
      sizeMaxPixels
    };
    model.shaderInputs.setProps({textBackground: textBackgroundProps});
    model.draw(this.context.renderPass);
  }

  protected _getModel(): Model {
    // a square that minimally cover the unit circle
    const positions = [0, 0, 1, 0, 0, 1, 1, 1];

    return new Model(this.context.device, {
      ...this.getShaders(),
      id: this.props.id,
      bufferLayout: this.getAttributeManager()!.getBufferLayouts(),
      geometry: new Geometry({
        topology: 'triangle-strip',
        vertexCount: 4,
        attributes: {
          positions: {size: 2, value: new Float32Array(positions)}
        }
      }),
      isInstanced: true
    });
  }
}