lib/heatmap/axes/axes.go

// Licensed to Apache Software Foundation (ASF) under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Apache Software Foundation (ASF) licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package axes

import (
	"image"

	"github.com/mum4k/termdash/private/runewidth"
)

const AxisWidth = 1

// YDetails contain information about the Y axis
// that will be drawn onto the canvas.
type YDetails struct {
	// Width in character cells of the Y axis and its character labels.
	Width int

	// Start is the point where the Y axis starts.
	// The Y coordinate of Start is less than the Y coordinate of End.
	Start image.Point

	// End is the point where the Y axis ends.
	End image.Point

	// Labels are the labels for values on the Y axis in an increasing order.
	Labels []*Label
}

// RequiredWidth calculates the minimum width required
// in order to draw the Y axis and its labels.
func RequiredWidth(max string) int {
	return runewidth.StringWidth(max) + AxisWidth
}

// NewYDetails retrieves details about the Y axis required
// to draw it on a canvas of the provided area.
func NewYDetails(stringLabels []string) (*YDetails, error) {
	graphHeight := len(stringLabels)

	// See how the labels would look like on the entire maxWidth.
	maxLabelWidth := LongestString(stringLabels)
	labels, err := yLabels(graphHeight, maxLabelWidth, stringLabels)
	if err != nil {
		return nil, err
	}

	width := maxLabelWidth + 1

	return &YDetails{
		Width:  width,
		Start:  image.Point{X: width - 1, Y: 0},
		End:    image.Point{X: width - 1, Y: graphHeight},
		Labels: labels,
	}, nil
}

// LongestString returns the length of the longest string in the string array.
func LongestString(strings []string) int {
	var widest int
	for _, s := range strings {
		if l := runewidth.StringWidth(s); l > widest {
			widest = l
		}
	}
	return widest
}

// XDetails contain information about the X axis
// that will be drawn onto the canvas.
type XDetails struct {
	// Start is the point where the X axis starts.
	// Both coordinates of Start are less than End.
	Start image.Point
	// End is the point where the X axis ends.
	End image.Point

	// Labels are the labels for values on the X axis in an increasing order.
	Labels []*Label
}

// NewXDetails retrieves details about the X axis required to draw it on a canvas
// of the provided area. The yStart is the point where the Y axis starts.
// The numPoints is the number of points in the largest series that will be
// plotted.
// customLabels are the desired labels for the X axis, these are preferred if
// provided.
func NewXDetails(cvsAr image.Rectangle, yEnd image.Point, stringLabels []string, cellWidth int) (*XDetails, error) {
	// The space between the start of the axis and the end of the canvas.
	// graphWidth := cvsAr.Dx() - yEnd.X - 1
	graphWidth := len(stringLabels) * cellWidth

	labels, err := xLabels(yEnd, graphWidth, stringLabels, cellWidth)
	if err != nil {
		return nil, err
	}

	return &XDetails{
		Start:  image.Point{yEnd.X, yEnd.Y - 1},
		End:    image.Point{yEnd.X + graphWidth, yEnd.Y - 1},
		Labels: labels,
	}, nil
}