Rendering of Segmented Numbers

majaak

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31 Jul 2015CPOL

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Explains how numbers can be rendered like segmented numbers (looking like old-school digital clock)

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Introduction

Before a while, I needed to implement rendering of numbers in one project (C++ MFC), where it wasn't possible to simply use rendering of text using font. So I made the prototype in C# WinForms and maybe someone will find it useful.

Background

I'm using classical old-school approach -> 7-segments rendering of numbers.

Source Code

I've created SegmentRender class for rendering of segmented numbers.

At first, I've created Enum of segment type for better orientation.

private enum Segment
{
    Up, LeftUp, RightUp, Middle, LeftDown, RightDown, Down
}

Here is simple 2D array [10 digits, 7 segments] for definition of segments used for each digit:

static int[,] segValues =
{
       {1, 1, 1, 0, 1, 1, 1},
       {0, 0, 1, 0, 0, 1, 0},
       {1, 0, 1, 1, 1, 0, 1},
       {1, 0, 1, 1, 0, 1, 1},
       {0, 1, 1, 1, 0, 1, 0},
       {1, 1, 0, 1, 0, 1, 1},
       {1, 1, 0, 1, 1, 1, 1},
       {1, 0, 1, 0, 0, 1, 0},
       {1, 1, 1, 1, 1, 1, 1},
       {1, 1, 1, 1, 0, 1, 1}
};

Then I defined 3 functions:

public void DrawNumber(int n, Graphics g, Point pos)

Here, the maximal order of our Int32 number is found:

while (true)
    if (n < Math.Pow(10, ++maxOrder))
        break;

Then, each single digit is found and called to be rendered:

for (int ord = 0; ord < maxOrder; ord++)
{
    int dig = n / Convert.ToInt32(Math.Pow(10, ord)) % 10;

    Point digPos = new Point
        (pos.X + (maxOrder - ord - 1) * (size + space), pos.Y);

    DrawDigit(dig, g, digPos);
}

The next function:

private void DrawDigit(int n, Graphics g, Point pos)

In this function, all single digits are called to be rendered:

for (int i = 0; i < 7; i++)
    if (segValues[n, i] == 1)
        DrawSegment((Segment)i, g, pos);

And the last rendering function:

private void DrawSegment(Segment s, Graphics g, Point pos)

Here I've defined all segments points (x, y) and rendered these segments, which are for actual digit enabled in variable segValues.

That's all, simple enough. The rest of the code is only handling of the application form.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

majaak

Software Developer

Czech Republic

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public class SegmentRender { int size; // digit width int lineWidth; // line width int space; // space between single digits Pen pen; // pen used for drawing of segments private static bool[,] segValues = { { true, true, true, false, true, true, true}, {false, false, true, false, false, true, false}, { true, false, true, true, true, false, true}, { true, false, true, true, false, true, true}, {false, true, true, true, false, true, false}, { true, true, false, true, false, true, true}, { true, true, false, true, true, true, true}, { true, false, true, false, false, true, false}, { true, true, true, true, true, true, true}, { true, true, true, true, false, true, true} }; private Size[] EndPointOffsets; private static readonly int[,] EndPointOffsetBase = { {0, 0}, {1, 0}, {0, 1}, {1, 1}, {0, 2}, {1, 2}, }; private enum Segment { Up, LeftUp, RightUp, Middle, LeftDown, RightDown, Down } public SegmentRender(int size, int space, Color color, int lineWidth = 1) { this.size = size; this.space = space; this.lineWidth = lineWidth; pen = new Pen(color, lineWidth); // precompute these! int endPoints = EndPointOffsetBase.GetLength(0); EndPointOffsets = new Size[endPoints]; for (int i = 0; i < endPoints; i++) { EndPointOffsets[i] = new Size(size * EndPointOffsetBase[i, 0], size * EndPointOffsetBase[i, 1]); } } // draw number by digital segments public void DrawNumber(int n, Graphics g, Point pos) { // we're ignoring negative numbers! if (n < 0) return; const int maxPossibleDigits = 10; // for int (32 bit) int[] digits = new int[maxPossibleDigits]; int digitPos = maxPossibleDigits; // collect the digits (from the low order end) at the same time as determining how many there are! do { int dig; n = Math.DivRem(n, 10, out dig); digits[--digitPos] = dig; } while (n > 0); // this loops through the digits in forward order int xoffset = 0; for (; digitPos < maxPossibleDigits; ++digitPos) { Point digPos = new Point(pos.X + xoffset, pos.Y); xoffset += size + space; DrawDigit(digits[digitPos], g, digPos); } } // draw single digit by digital segments private void DrawDigit(int n, Graphics g, Point pos) { for (Segment s = Segment.Up; s <= Segment.Down; ++s) if (segValues[n, (int)s]) DrawSegment(s, g, pos); } // draw single segment private void DrawSegment(Segment s, Graphics g, Point pos) { switch (s) { case Segment.Up: g.DrawLine(pen, pos + EndPointOffsets[0], pos + EndPointOffsets[1]); break; case Segment.LeftUp: g.DrawLine(pen, pos + EndPointOffsets[0], pos + EndPointOffsets[2]); break; case Segment.RightUp: g.DrawLine(pen, pos + EndPointOffsets[1], pos + EndPointOffsets[3]); break; case Segment.Middle: g.DrawLine(pen, pos + EndPointOffsets[2], pos + EndPointOffsets[3]); break; case Segment.LeftDown: g.DrawLine(pen, pos + EndPointOffsets[2], pos + EndPointOffsets[4]); break; case Segment.RightDown: g.DrawLine(pen, pos + EndPointOffsets[3], pos + EndPointOffsets[5]); break; case Segment.Down: g.DrawLine(pen, pos + EndPointOffsets[4], pos + EndPointOffsets[5]); break; default: break; } } }

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Rendering of Segmented Numbers

Introduction

Background

Source Code

License

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