package goterm import ( "fmt" "math" "strings" ) const ( AXIS_LEFT = iota AXIS_RIGHT ) const ( DRAW_INDEPENDENT = 1 << iota DRAW_RELATIVE ) type DataTable struct { columns []string rows [][]float64 } func (d *DataTable) AddColumn(name string) { d.columns = append(d.columns, name) } func (d *DataTable) AddRow(elms ...float64) { d.rows = append(d.rows, elms) } type Chart interface { Draw(data DataTable, flags int) string } type LineChart struct { Buf []string chartBuf []string data *DataTable Width int Height int chartHeight int chartWidth int paddingX int paddingY int Flags int } func genBuf(size int) []string { buf := make([]string, size) for i := 0; i < size; i++ { buf[i] = " " } return buf } // Format float func ff(num interface{}) string { return fmt.Sprintf("%.1f", num) } func NewLineChart(width, height int) *LineChart { chart := new(LineChart) chart.Width = width chart.Height = height chart.Buf = genBuf(width * height) // axis lines + axies text chart.paddingY = 2 return chart } func (c *LineChart) DrawAxes(maxX, minX, maxY, minY float64, index int) { side := AXIS_LEFT if c.Flags&DRAW_INDEPENDENT != 0 { if index%2 == 0 { side = AXIS_RIGHT } c.DrawLine(c.paddingX-1, 1, c.Width-c.paddingX, 1, "-") } else { c.DrawLine(c.paddingX-1, 1, c.Width-1, 1, "-") } if side == AXIS_LEFT { c.DrawLine(c.paddingX-1, 1, c.paddingX-1, c.Height-1, "│") } else { c.DrawLine(c.Width-c.paddingX, 1, c.Width-c.paddingX, c.Height-1, "│") } left := 0 if side == AXIS_RIGHT { left = c.Width - c.paddingX + 1 } if c.Flags&DRAW_RELATIVE != 0 { c.writeText(ff(minY), left, 1) } else { if minY > 0 { c.writeText("0", left, 1) } else { c.writeText(ff(minY), left, 1) } } c.writeText(ff(maxY), left, c.Height-1) c.writeText(ff(minX), c.paddingX, 0) x_col := c.data.columns[0] c.writeText(c.data.columns[0], c.Width/2-len(x_col)/2, 1) if c.Flags&DRAW_INDEPENDENT != 0 || len(c.data.columns) < 3 { col := c.data.columns[index] for idx, char := range strings.Split(col, "") { start_from := c.Height/2 + len(col)/2 - idx if side == AXIS_LEFT { c.writeText(char, c.paddingX-1, start_from) } else { c.writeText(char, c.Width-c.paddingX, start_from) } } } if c.Flags&DRAW_INDEPENDENT != 0 { c.writeText(ff(maxX), c.Width-c.paddingX-len(ff(maxX)), 0) } else { c.writeText(ff(maxX), c.Width-len(ff(maxX)), 0) } } func (c *LineChart) writeText(text string, x, y int) { coord := y*c.Width + x for idx, char := range strings.Split(text, "") { c.Buf[coord+idx] = char } } func (c *LineChart) Draw(data *DataTable) (out string) { var scaleY, scaleX float64 c.data = data if c.Flags&DRAW_INDEPENDENT != 0 && len(data.columns) > 3 { fmt.Println("Error: Can't use DRAW_INDEPENDENT for more then 2 graphs") return "" } charts := len(data.columns) - 1 prevPoint := [2]int{-1, -1} maxX, minX, maxY, minY := getBoundaryValues(data, -1) c.paddingX = int(math.Max(float64(len(ff(minY))), float64(len(ff(maxY))))) + 1 c.chartHeight = c.Height - c.paddingY if c.Flags&DRAW_INDEPENDENT != 0 { c.chartWidth = c.Width - 2*c.paddingX } else { c.chartWidth = c.Width - c.paddingX - 1 } scaleX = float64(c.chartWidth) / (maxX - minX) if c.Flags&DRAW_RELATIVE != 0 || minY < 0 { scaleY = float64(c.chartHeight) / (maxY - minY) } else { scaleY = float64(c.chartHeight) / maxY } for i := 1; i < charts+1; i++ { if c.Flags&DRAW_INDEPENDENT != 0 { maxX, minX, maxY, minY = getBoundaryValues(data, i) scaleX = float64(c.chartWidth-1) / (maxX - minX) scaleY = float64(c.chartHeight) / maxY if c.Flags&DRAW_RELATIVE != 0 || minY < 0 { scaleY = float64(c.chartHeight) / (maxY - minY) } } symbol := Color("•", i) c_data := getChartData(data, i) for _, point := range c_data { x := int((point[0]-minX)*scaleX) + c.paddingX y := int((point[1])*scaleY) + c.paddingY if c.Flags&DRAW_RELATIVE != 0 || minY < 0 { y = int((point[1]-minY)*scaleY) + c.paddingY } if prevPoint[0] == -1 { prevPoint[0] = x prevPoint[1] = y } if prevPoint[0] <= x { c.DrawLine(prevPoint[0], prevPoint[1], x, y, symbol) } prevPoint[0] = x prevPoint[1] = y } c.DrawAxes(maxX, minX, maxY, minY, i) } for row := c.Height - 1; row >= 0; row-- { out += strings.Join(c.Buf[row*c.Width:(row+1)*c.Width], "") + "\n" } return } func (c *LineChart) DrawLine(x0, y0, x1, y1 int, symbol string) { drawLine(x0, y0, x1, y1, func(x, y int) { coord := y*c.Width + x if coord > 0 && coord < len(c.Buf) { c.Buf[coord] = symbol } }) } func getBoundaryValues(data *DataTable, index int) (maxX, minX, maxY, minY float64) { maxX = data.rows[0][0] minX = data.rows[0][0] maxY = data.rows[0][1] minY = data.rows[0][1] for _, r := range data.rows { maxX = math.Max(maxX, r[0]) minX = math.Min(minX, r[0]) for idx, c := range r { if idx > 0 { if index == -1 || index == idx { maxY = math.Max(maxY, c) minY = math.Min(minY, c) } } } } if maxY > 0 { maxY = maxY * 1.1 } else { maxY = maxY * 0.9 } if minY > 0 { minY = minY * 0.9 } else { minY = minY * 1.1 } return } // DataTable can contain data for multiple graphs, we need to extract only 1 func getChartData(data *DataTable, index int) (out [][]float64) { for _, r := range data.rows { out = append(out, []float64{r[0], r[index]}) } return } // Algorithm for drawing line between two points // // http://en.wikipedia.org/wiki/Bresenham's_line_algorithm func drawLine(x0, y0, x1, y1 int, plot func(int, int)) { dx := x1 - x0 if dx < 0 { dx = -dx } dy := y1 - y0 if dy < 0 { dy = -dy } var sx, sy int if x0 < x1 { sx = 1 } else { sx = -1 } if y0 < y1 { sy = 1 } else { sy = -1 } err := dx - dy for { plot(x0, y0) if x0 == x1 && y0 == y1 { break } e2 := 2 * err if e2 > -dy { err -= dy x0 += sx } if e2 < dx { err += dx y0 += sy } } }