SyntaxBomb - Indie Coders

; ----------------------------------------
; Name : Draw 2D Charts functions
; Date : (C)2025 
; Site : https://github.com/BlackCreepyCat
; ----------------------------------------


; Define a Type for individual values
Type ChartValue
    Field value#          ; The value of the bar
    Field parent.Chart    ; Link to the parent Chart
    Field nextValue.ChartValue ; Link to the next ChartValue (linked list)
End Type

; Define a Type for the chart itself
Type Chart
    Field name$           ; Name of the chart
    Field firstValue.ChartValue ; Pointer to the first ChartValue
End Type

; Function to add a value to a Chart
Function AddChartValue(c.Chart, value#)
    Local cv.ChartValue = New ChartValue
    cv\value = value
    cv\parent = c
    
    ; If this is the first value, set it as firstValue
    If c\firstValue = Null Then
        c\firstValue = cv
    Else
        ; Find the last value and link the new one
        Local lastValue.ChartValue = c\firstValue
        While lastValue\nextValue <> Null
            lastValue = lastValue\nextValue
        Wend
        lastValue\nextValue = cv
    End If
End Function

; Function to draw a bar chart
Function DrawBarChart(c.Chart, x%, y%, width%, height%)
    ; c: Chart instance to draw
    ; x, y: top-left position of the chart
    ; width, height: dimensions of the chart
	
    ; Count the number of bars
    Local numBars% = 0
    Local cv.ChartValue = c\firstValue
    While cv <> Null
        numBars = numBars + 1
        cv = cv\nextValue
    Wend
    
    If numBars = 0 Then Return ; Exit if there's no data
	
    Local barWidth% = width / numBars ; Width of each bar
    Local maxValue# = 0
	
    ; Find the maximum value for normalization
    cv = c\firstValue
    While cv <> Null
        If cv\value > maxValue Then maxValue = cv\value
        cv = cv\nextValue
    Wend
	
    ; Draw each bar
    Local i% = 0
    cv = c\firstValue
    While cv <> Null
        Local barHeight% = (cv\value / maxValue) * height
        Local barX% = x + i * barWidth
        Local barY% = y + height - barHeight
		
        Color 0, 255, 0 ; Green color for the bar
        Rect barX, barY, barWidth - 2, barHeight, 1 ; -2 for spacing between bars
		
        Color 255, 255, 255 ; White color for text
        Text barX + barWidth / 2, y + height + 5, Str(cv\value), True ; Label with value
		
        i = i + 1
        cv = cv\nextValue
    Wend
	
    ; Draw the axes
    Color 255, 255, 255 ; White color for axes
    Line x, y, x, y + height ; Y-axis
    Line x, y + height, x + width, y + height ; X-axis
	
    ; Display the chart name
    If c\name <> "" Then
        Text x + width / 2, y - 20, c\name, True ; Centered above the chart
    End If
End Function

; Example usage
Graphics 800, 600, 0, 2 ; Windowed mode
SetBuffer BackBuffer()

; Create a chart
Local myChart.Chart = New Chart
myChart\name = "My Chart"

; Add values to the chart
AddChartValue(myChart, 10)
AddChartValue(myChart, 500)
AddChartValue(myChart, 30)
AddChartValue(myChart, 70)
AddChartValue(myChart, 200)

Repeat
    Cls
    DrawBarChart(myChart, 100, 100, 300, 200)
    Flip
Until KeyHit(1) ; Exit with Esc key

; Clean up instances
Local cv.ChartValue = myChart\firstValue
While cv <> Null
    Local nextCv.ChartValue = cv\nextValue
    Delete cv
    cv = nextCv
Wend
Delete myChart

End