#define N_SWIMAGE_TYPE_RGB (0)
#define N_SWIMAGE_TYPE_RGBA (1)
typedef struct _SSWImage {
    uint32_t unType;

    uint32_t unWidth;
    uint32_t unHeight;

    uint32_t unPadding;

    // 16Bytes.

    uint8_t* pData;
} SSWImage;

Public Const IMAGE_FORMAT_TYPE_RGB As Integer = 0
Public Const IMAGE_FORMAT_TYPE_RGBA As Integer = 1
Public Const IMAGE_STRUCTURE_HEADER_SIZE As Integer = 16
Public Type SWImageStructure
    format As Long
    width As Long
    height As Long
    padding As Long
    
    data() As Byte
End Type
Public Type SWImage
    id As Integer
    image As SWImageStructure
End Type
Sub LoadImage(ByRef rImageStructure As SWImageStructure, ByRef szFileName As String)
    Dim fd As Integer
    Dim nSize As Long
    Dim aBuff() As Byte
    
    Dim nCount As Integer
    nCount = 0
    
    fd = FreeFile
    
    ' 対象のファイルを開く.
    Open szFileName For Binary Access Read As #fd
    
    ' 配列の確保.
    ReDim aBuff(IMAGE_STRUCTURE_HEADER_SIZE)
    
    ' データの読み込み.
    aBuff = InputB(IMAGE_STRUCTURE_HEADER_SIZE, fd)
    
    ' 最初の4Bytesはフォーマット番号だが、0か1にしかなり得ないので先頭の1Byteのみで良い.
    rImageStructure.format = aBuff(nCount)
    nCount = nCount + 4
    
    ' 次の4Bytesが幅( uint32_t ).
    rImageStructure.width = aBuff(nCount) + 255 * aBuff(nCount + 1) + 65535 * aBuff(nCount + 2) + 16711680 * aBuff(nCount + 3)
    nCount = nCount + 4
    
    ' その次の4Bytesが高さ( uint32_t ).
    rImageStructure.height = aBuff(nCount) + 255 * aBuff(nCount + 1) + 65535 * aBuff(nCount + 2) + 16711680 * aBuff(nCount + 3)
    
    ' その次はPaddingなので、気にしない.
    rImageStructure.padding = 0
    
    ' データ部分のサイズを取得.
    nSize = LOF(fd) - IMAGE_STRUCTURE_HEADER_SIZE
    
    ' データ部分のサイズに合わせて配列のサイズを変更.
    ReDim rImageStructure.data(nSize)
    
    ' データの読み込み.
    rImageStructure.data = InputB(nSize, fd)
    
    ' 対象のファイルを閉じる.
    Close #fd
    
End Sub
Sub TestLoadImage()
    ' まずは有効なデータの数を調べる
    Dim nRowCnt As Integer
    Dim nElementCnt As Integer
    
    ' 画像の実体
    Dim aImage() As SWImage
    
    Dim nRows As Integer
    With Worksheets("ImageLoadTest")
        nRows = .Cells(.Rows.Count, 1).End(xlUp).Row - 1
    End With
    
    ReDim aImage(nRows - 1)
    
    For nRowCnt = 2 To 2 + nRows - 1
        With Worksheets("ImageLoadTest")
            ' 1列目が画像の番号.
            aImage(nElementCnt).id = .Cells(nRowCnt, 1).Value
            
            ' 2列目が画像のファイルの場所.
            Call LoadImage(aImage(nElementCnt).image, ThisWorkbook.Path & "\" & .Cells(nRowCnt, 2).Value)
            
            nElementCnt = nElementCnt + 1
        End With
    Next
End Sub

Public Type SWImageDraw
    pos As Position
    sSWImage As SWImage
End Type

Sub SetupImage(ByRef aImage() As SWImageDraw)
    ' まずはimageシートの有効な行の数を調べる.
    Dim nRowCnt As Integer
    Dim nElementCnt As Integer
    
    Dim nRows As Integer
    With Worksheets("image")
        nRows = .Cells(.Rows.Count, 1).End(xlUp).Row - 1
    End With
    
    ReDim aImage(nRows - 1)
    
    For nRowCnt = 2 To 2 + nRows - 1
        With Worksheets("image")
            ' 1列目が管理番号.
            aImage(nElementCnt).sSWImage.id = .Cells(nRowCnt, 1).Value
            
            ' 2列目はファイル名なので、ここで画像の読み込み処理をコール.
            Call LoadImage(aImage(nElementCnt).sSWImage.image, ThisWorkbook.Path & "\" & .Cells(nRowCnt, 2).Value)
            
            ' 3列目は位置.
            aImage(nElementCnt).pos.x = .Cells(nRowCnt, 3).Value
            aImage(nElementCnt).pos.y = .Cells(nRowCnt, 4).Value
            
            nElementCnt = nElementCnt + 1
        End With
    Next
    
End Sub

Sub DrawImage(ByRef rImage As SWImageDraw)
    ' rImage.sSWImage.image.dataの内容をコピーする.
    Dim nRowStart As Long
    Dim nColStart As Long
    
    ' カウンタ変数を用意.
    Dim nRowCnt As Long: nRowCnt = 0
    Dim nColCnt As Long: nColCnt = 0
    
    ' 読み込んだ画像データ上のピクセルの開始位置.
    Dim nPixelPosition As Long: nPixelPosition = 0
    
    ' 色を一時的に格納する変数.
    Dim sColor As ColorRGB
    
    ' ピクセル辺り何Bytesか( デフォルトは4 ).
    Dim nBytesPerPixel As Integer: nBytesPerPixel = 4
    
    ' ただし、画像フォーマットが0番の場合は3.
    If IMAGE_FORMAT_TYPE_RGB = rImage.sSWImage.image.format Then
        nBytesPerPixel = 3
    End If
    
    nRowStart = rImage.pos.y + 1
    nColStart = rImage.pos.x + 1
    
    With Worksheets("framebuffer")
        ' 幅( 列 )を塗りきったら改行.
        For nRowCnt = 0 To rImage.sSWImage.image.height - 1
            For nColCnt = 0 To rImage.sSWImage.image.width - 1
                ' 読み込んだ画像データ上の位置.
                nPixelPosition = nBytesPerPixel * (nColCnt + nRowCnt * rImage.sSWImage.image.width)
                
                ' この形式では色はRGB(A)の順番で格納されている.
                ' まだアルファチャネルは考慮しない.
                sColor.R = rImage.sSWImage.image.data(nPixelPosition)
                sColor.G = rImage.sSWImage.image.data(nPixelPosition + 1)
                sColor.B = rImage.sSWImage.image.data(nPixelPosition + 2)
                .Cells(nRowStart + nRowCnt, nColStart + nColCnt).Interior.color = RGB(sColor.R, sColor.G, sColor.B)
            Next nColCnt
        Next nRowCnt
    End With
End Sub

Sub Main()
    Dim cRenderSystem As RenderingSystem
    Set cRenderSystem = New RenderingSystem
    
    ' Rectの格納場所を用意.
    Dim aRect() As Rect
    Dim nCnt As Integer
    
    ' Imageの格納場所を用意.
    Dim aImage() As SWImageDraw
        
    ' 初期化処理をコール.
    Call Initialize(cRenderSystem)
    
    ' rectシートから、Rectをセットアップ.
    Call SetupRect(aRect)
    
    ' imageシートから、SWImageDrawをセットアップ.
    Call SetupImage(aImage)
    
    ' aRectの要素数に合わせてRenderingSystemのDrawRectをコール.
    For nCnt = LBound(aRect) To UBound(aRect)
        Call cRenderSystem.DrawRect(aRect(nCnt))
    Next
    
    ' aImageの要素数に合わせてRenderingSystemのDrawImageをコール.
    For nCnt = LBound(aImage) To UBound(aImage)
        Call cRenderSystem.DrawImage(aImage(nCnt))
    Next
    
    ' 終了処理をコール.
    Call Terminate(cRenderSystem)
End Sub