Returns one or more histograms for specified color channels of the specified Bitmap
#include <GDIPlus.au3>
_GDIPlus_BitmapGetHistogram ( $hBitmap, $iHistogramFormat, $iHistogramSize, $tChannel_0 [, $tChannel_1 = 0 [, $tChannel_2 = 0 [, $tChannel_3 = 0]]] )
| $hBitmap | Handle to a Bitmap to which the effect is applied. |
| $iHistogramFormat | HistogramFormat constant that specifies the channels for which histograms will be created ($GDIP_HistogramFormat*). |
| $iHistogramSize | Number of elements in each of the arrays pointed to by $tChannel_0, $tChannel_1, $tChannel_2, and $tChannel_3? |
| $tChannel_0 | A DLL struct array of UINTs that receives the first histogram. |
| $tChannel_1 | [optional] A DLL struct array of UINTs that receives the second histogram if there is a second histogram. Pass NULL if there is no second histogram. |
| $tChannel_2 | [optional] A DLL struct array of UINTs that receives the third histogram if there is a third histogram. Pass NULL if there is no third histogram. |
| $tChannel_3 | [optional] A DLL struct array of UINTs that receives the fourth histogram if there is a fourth histogram. Pass NULL if there is no fourth histogram. |
| Success: | True. |
| Failure: | False and sets the @error flag to non-zero, @extended may contain GPSTATUS error code ($GPIP_ERR* see GPIPlusConstants.au3). |
| @error: | -1 - GDIPlus.dll does not support this function. 10 - Invalid parameters. |
The number of histograms returned depends on the $iHistogramFormat parameter. For example, if format is equal to $GDIP_HistogramFormatRGB, then three histograms are returned: one each for the red, green, and blue channels. In that case, $tChannel_0 receives the red-channel histogram, $tChannel_1 receives the green-channel histogram, and $tChannel_2 receives the blue-channel histogram. For $GDIP_HistogramFormatRGB, $tChannel_3 must be set to NULL because there is no fourth histogram
_GDIPlus_BitmapGetHistogramEx, _GDIPlus_BitmapGetHistogramSize
Search GdipBitmapGetHistogram in MSDN Library.
#include <GDIPlus.au3>
#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>
#include <WindowsConstants.au3>
Opt("GUIOnEventMode", 1)
Global $g_idCombo, $g_hGfx_Buffer, $g_hGfx_Buffer_H, $g_hGui, $g_hGraphics, $g_hGraphics_H, $g_hBmp_Buffer_H, $g_hImage, $g_hBmp_Buffer, $g_hGui_Histogram
Global $g_tChannel, $g_iMaxLum
_Example()
Func _Example()
If Not _GDIPlus_Startup() Or @extended < 6 Then
MsgBox($MB_SYSTEMMODAL, "ERROR", "GDIPlus.dll v1.1 not available")
Return
EndIf
Local $sFile = FileOpenDialog("Select an image", "", "Images (*.bmp;*.png;*.jpg;*.gif;*.tif)")
If @error Or Not FileExists($sFile) Then Return
$g_hImage = _GDIPlus_ImageLoadFromFile($sFile)
Local $iWidth = 600
Local $iHeight = _GDIPlus_ImageGetHeight($g_hImage) * 600 / _GDIPlus_ImageGetWidth($g_hImage)
$g_hGui = GUICreate("GDI+ v1.1 (" & @ScriptName & ")", $iWidth, $iHeight)
GUISetOnEvent($GUI_EVENT_CLOSE, "_Exit")
$g_hGraphics = _GDIPlus_GraphicsCreateFromHWND($g_hGui)
$g_hBmp_Buffer = _GDIPlus_BitmapCreateFromScan0($iWidth, $iHeight)
$g_hGfx_Buffer = _GDIPlus_ImageGetGraphicsContext($g_hBmp_Buffer)
_GDIPlus_GraphicsDrawImageRect($g_hGfx_Buffer, $g_hImage, 0, 0, $iWidth, $iHeight)
$g_hGui_Histogram = GUICreate("Histogram", 266, 160)
GUISetOnEvent($GUI_EVENT_CLOSE, "_Exit")
$g_idCombo = GUICtrlCreateCombo("", 10, 132, 246, 20)
GUICtrlSetData(-1, "Alpha|Red|Green|Blue|Grey", "Red")
GUICtrlSetOnEvent(-1, "_CreateHistogram")
$g_hGraphics_H = _GDIPlus_GraphicsCreateFromHWND($g_hGui_Histogram)
$g_hBmp_Buffer_H = _GDIPlus_BitmapCreateFromScan0(259, 122)
$g_hGfx_Buffer_H = _GDIPlus_ImageGetGraphicsContext($g_hBmp_Buffer_H)
_GDIPlus_GraphicsSetSmoothingMode($g_hGfx_Buffer_H, $GDIP_SMOOTHINGMODE_HIGHQUALITY)
$g_iMaxLum = _GetHistogramMaxLum()
_CreateHistogram()
GUIRegisterMsg($WM_PAINT, "WM_PAINT")
GUIRegisterMsg($WM_ERASEBKGND, "WM_PAINT")
GUISetState(@SW_SHOW, $g_hGui)
GUISetState(@SW_SHOW, $g_hGui_Histogram)
GUISetOnEvent($GUI_EVENT_MOUSEMOVE, "_ToolTip", $g_hGui_Histogram)
While Sleep(10)
WEnd
EndFunc ;==>_Example
Func _ToolTip()
Local $aInfo = GUIGetCursorInfo($g_hGui_Histogram)
If IsArray($aInfo) Then
If $aInfo[0] < 0 Or $aInfo[0] > 266 Or $aInfo[1] < 0 Or $aInfo[1] > 160 Then Return
Local $iIndex = $aInfo[0] - 5
If $iIndex < 1 Then
$iIndex = 1
ElseIf $iIndex > 256 Then
$iIndex = 256
EndIf
Local $iValue = DllStructGetData($g_tChannel, 1, $iIndex)
ToolTip("Index: " & $iIndex & ", Value: " & $iValue)
EndIf
EndFunc ;==>_ToolTip
Func _GetHistogramMaxLum()
Local $iSize = _GDIPlus_BitmapGetHistogramSize($GDIP_HistogramFormatGray)
Local $tChannel_Grey = DllStructCreate("uint[" & $iSize & "];")
_GDIPlus_BitmapGetHistogram($g_hImage, $GDIP_HistogramFormatGray, $iSize, $tChannel_Grey)
Local $iMaxLum = 0
For $i = 1 To $iSize
If DllStructGetData($tChannel_Grey, 1, $i) > $iMaxLum Then $iMaxLum = DllStructGetData($tChannel_Grey, 1, $i)
Next
Return $iMaxLum
EndFunc ;==>_GetHistogramMaxLum
Func _CreateHistogram()
Local $iHistogramFormat, $iColor
Switch GUICtrlRead($g_idCombo)
Case "Alpha"
$iHistogramFormat = $GDIP_HistogramFormatA
$iColor = 0xFFFF00FF
Case "Red"
$iHistogramFormat = $GDIP_HistogramFormatR
$iColor = 0xFFFF0000
Case "Green"
$iHistogramFormat = $GDIP_HistogramFormatG
$iColor = 0xFF00FF00
Case "Blue"
$iHistogramFormat = $GDIP_HistogramFormatB
$iColor = 0xFF0000FF
Case "Grey"
$iHistogramFormat = $GDIP_HistogramFormatGray
$iColor = 0xFFFFFFFF
Case Else
Return
EndSwitch
Local $iSize = _GDIPlus_BitmapGetHistogramSize($iHistogramFormat)
$g_tChannel = DllStructCreate("uint[" & $iSize & "];")
_GDIPlus_BitmapGetHistogram($g_hImage, $iHistogramFormat, $iSize, $g_tChannel)
Local $fScale = 1 / $g_iMaxLum * 100
Local $aPoly[$iSize + 3][2] = [[$iSize + 2]]
For $i = 1 To $iSize
$aPoly[$i][0] = $i
$aPoly[$i][1] = 100 - DllStructGetData($g_tChannel, 1, $i) * $fScale
Next
$aPoly[$iSize + 1][0] = $iSize + 1
$aPoly[$iSize + 1][1] = 100
$aPoly[$iSize + 2][0] = 1
$aPoly[$iSize + 2][1] = 100
_GDIPlus_GraphicsClear($g_hGfx_Buffer_H, 0xFFFFFFFF)
Local $hBrush = _GDIPlus_LineBrushCreate(1, 0, 258, 0, 0xFF000000, $iColor)
_GDIPlus_GraphicsFillPolygon($g_hGfx_Buffer_H, $aPoly, $hBrush)
_GDIPlus_GraphicsFillRect($g_hGfx_Buffer_H, 1, 104, 256, 16, $hBrush)
_GDIPlus_BrushDispose($hBrush)
Local $hPen = _GDIPlus_PenCreate(0xFF000000)
_GDIPlus_GraphicsDrawPolygon($g_hGfx_Buffer_H, $aPoly, $hPen)
_GDIPlus_GraphicsDrawRect($g_hGfx_Buffer_H, 0, 0, 258, 100, $hPen)
_GDIPlus_GraphicsDrawRect($g_hGfx_Buffer_H, 0, 103, 258, 18, $hPen)
_GDIPlus_PenDispose($hPen)
_GDIPlus_GraphicsDrawImage($g_hGraphics_H, $g_hBmp_Buffer_H, 4, 4)
EndFunc ;==>_CreateHistogram
Func WM_PAINT($hWnd, $iMsgm, $wParam, $lParam)
#forceref $iMsgm, $wParam, $lParam
Switch $hWnd
Case $g_hGui
_GDIPlus_GraphicsDrawImage($g_hGraphics, $g_hBmp_Buffer, 0, 0)
Case $g_hGui_Histogram
_GDIPlus_GraphicsDrawImage($g_hGraphics_H, $g_hBmp_Buffer_H, 4, 4)
EndSwitch
Return $GUI_RUNDEFMSG
EndFunc ;==>WM_PAINT
Func _Exit()
_GDIPlus_ImageDispose($g_hImage)
_GDIPlus_GraphicsDispose($g_hGfx_Buffer_H)
_GDIPlus_BitmapDispose($g_hBmp_Buffer_H)
_GDIPlus_GraphicsDispose($g_hGraphics_H)
_GDIPlus_GraphicsDispose($g_hGfx_Buffer)
_GDIPlus_BitmapDispose($g_hBmp_Buffer)
_GDIPlus_GraphicsDispose($g_hGraphics)
_GDIPlus_Shutdown()
Exit
EndFunc ;==>_Exit