Graphics

jgershonw1 wrote:

This is probably the worst way of doing it

Aaron Stubbendieck wrote:

Is DirectX overkill and is it fast enough in a managed environment? Is there a third option I'm not thinking of?

Aaron Stubbendieck wrote:

I keep meaning to learn DX and I'd appreciate taking a look at what you've got to get me started.

Public Module GraphicsIO

    Private Header() As Byte
    Private HeaderLen As Integer

    Private PixelArray(,) As PixelStr
    Public Width As Integer
    Public Height As Integer

    'reads the data from a filestream into the header and pixelarray
    Public Sub ReadStream(ByVal fstream As IO.FileStream)
        Dim bytearray() As Byte, len As Integer, rowoffset As Integer, offset As Integer
        Dim n As Integer, x As Integer, y As Integer, padding As Integer
        Dim remainder As Integer

        len = fstream.Length
        ReDim bytearray(len)
        fstream.Read(bytearray, 0, len) 'copies file stream into an array

        'this extracts header information
        HeaderLen = System.BitConverter.ToInt32(bytearray, 10)
        Width = System.BitConverter.ToInt32(bytearray, 18)
        Height = System.BitConverter.ToInt32(bytearray, 22)
        ReDim PixelArray(Width, Height)

        'this copies the header information into its own array
        ReDim Header(HeaderLen)
        For n = 0 To (HeaderLen - 1)
            Header(n) = bytearray(n)
        Next

        'each row in a bitmap file must be a multiple of 4
        'If not empty padding bytes are added
        'This takes that into account and calculates how many padding bytes were added
        remainder = (Width * 3) Mod 4
        If remainder > 0 Then
            padding = 4 - remainder
        Else
            padding = 0
        End If

        'this extracts the data and puts it into a 2d array of structures representing the colors
        For y = 1 To Height
            rowoffset = ((y - 1) * ((3 * Width) + padding))
            offset = rowoffset + HeaderLen
            For x = 1 To Width
                'bitmaps store colors in reverse order: blue, green, red
                PixelArray(x, y).B = bytearray(offset) 'blue
                offset += 1
                PixelArray(x, y).G = bytearray(offset) 'green
                offset += 1
                PixelArray(x, y).R = bytearray(offset) 'red
                offset += 1
            Next
        Next

    End Sub

    'displays the image on the picturebox
    Public Sub WriteToPictureBox(ByVal pictbox As PictureBox)
        Dim myimage As Image, mstream As New IO.MemoryStream

        mstream = GraphicsIO.WriteStream(mstream)

        myimage = Image.FromStream(mstream)
        pictbox.Image = myimage
        Form1.GloImage = myimage
    End Sub

    'creates a file stream from the pixelarray
    Public Function WriteStream(ByVal mstream As IO.MemoryStream)
        Dim rowoffset As Integer, offset As Integer, bytearray() As Byte, len As Integer
        Dim n As Integer, x As Integer, y As Integer, padding As Integer
        Dim remainder As Integer

        'Each row in a bitmap file must be a multiple of 4
        'If not empty padding bytes are added
        'This takes that into account and calculates how many padding bytes to add
        remainder = (Width * 3) Mod 4
        If remainder > 0 Then
            padding = 4 - remainder
        Else
            padding = 0
        End If

        len = HeaderLen + (Height * ((Width * 3) + padding))
        ReDim bytearray(len)

        'copies the header into the byte array
        For n = 0 To (HeaderLen - 1)
            bytearray(n) = Header(n)
        Next

        'this extracts the data from a 2d array of structures representing the colors
        For y = 1 To Height
            rowoffset = ((y - 1) * ((3 * Width) + padding))
            offset = rowoffset + HeaderLen
            For x = 1 To Width
                'bitmaps store colors in reverse order: blue, green, red
                bytearray(offset) = PixelArray(x, y).B
                offset += 1
                bytearray(offset) = PixelArray(x, y).G
                offset += 1
                bytearray(offset) = PixelArray(x, y).R
                offset += 1
            Next
        Next

        'copies the bytearray into the memory stream
        mstream.Write(bytearray, 0, len)

        Return mstream
    End Function

    'reads a pixel
    Public Sub GetPixel(ByVal x As Integer, ByVal y As Integer, ByRef r As Integer, ByRef g As Integer, ByRef b As Integer)
        Dim pixel As PixelStr

        pixel = PixelArray(x, y)
        r = pixel.R
        g = pixel.G
        b = pixel.B

    End Sub

    'reads a pixel
    Public Function GetPixel(ByVal x As Integer, ByVal y As Integer) As PixelStr
        Dim pixel As PixelStr

        pixel = PixelArray(x, y)

        Return pixel
    End Function

    'writes a pixel
    Public Sub SetPixel(ByVal x As Integer, ByVal y As Integer, ByVal r As Integer, ByVal g As Integer, ByVal b As Integer)

        PixelArray(x, y).R = r
        PixelArray(x, y).G = g
        PixelArray(x, y).B = b

    End Sub


    Public Structure PixelStr
        Public R As Byte 'red
        Public G As Byte 'green
        Public B As Byte 'blue
    End Structure


End Module

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using Microsoft.DirectX;
using Microsoft.DirectX.DirectDraw;

#include <atlimage.h>

...

    CFileDialog cFileDlg( TRUE, NULL, NULL, OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT, _T("File(*.JPEG;*.JPG;*.BMP;*.PNG;*.TIF;*.GIF)|*.JPEG;*.JPG;*.BMP;*.PNG;*.TIF;*.GIF||"), NULL);
      
    if (IDOK == cFileDlg.DoModal())
    {
        CString strPicFilePath = cFileDlg.GetPathName();

        CImage SrcBitmap;
        SrcBitmap.Load(strPicFilePath);

        CClientDC dc(this);

        SrcBitmap.Draw(dc, 0, 0);

        SrcBitmap.Destroy();
    }

Mark Salsbery
Microsoft MVP - Visual C++