7 files changed, 53 insertions, 7 deletions
diff --git a/src/nigui.nim b/src/nigui.nim
index f4e49ef..d0281b6 100755
--- a/src/nigui.nim
+++ b/src/nigui.nim
@@ -487,6 +487,10 @@ method height*(image: Image): int
 
 method canvas*(image: Image): Canvas
 
+method beginPixelDataAccess*(image: Image): ptr UncheckedArray[byte]
+
+method endPixelDataAccess*(image: Image)
+
 
 # ----------------------------------------------------------------------------------------
 #                                        Window
diff --git a/src/nigui/private/gtk3/gtk3.nim b/src/nigui/private/gtk3/gtk3.nim
index f9c666f..108a310 100755
--- a/src/nigui/private/gtk3/gtk3.nim
+++ b/src/nigui/private/gtk3/gtk3.nim
@@ -438,7 +438,7 @@ proc cairo_image_surface_create*(format: cint, width, height: cint): pointer {.i
 proc cairo_image_surface_get_width*(surface: pointer): cint {.importc: "cairo_image_surface_get_width", libgtk3.}
 proc cairo_image_surface_get_height*(surface: pointer): cint {.importc: "cairo_image_surface_get_height", libgtk3.}
 proc cairo_image_surface_get_stride*(surface: pointer): cint {.importc: "cairo_image_surface_get_stride", libgtk3.}
-proc cairo_image_surface_get_data*(surface: pointer): cstring {.importc: "cairo_image_surface_get_data", libgtk3.}
+proc cairo_image_surface_get_data*(surface: pointer): ptr UncheckedArray[byte] {.importc: "cairo_image_surface_get_data", libgtk3.}
 proc cairo_surface_flush*(surface: pointer) {.importc: "cairo_surface_flush", libgtk3.}
 proc cairo_surface_mark_dirty*(surface: pointer) {.importc: "cairo_surface_mark_dirty", libgtk3.}
 proc cairo_surface_destroy*(surface: pointer) {.importc: "cairo_surface_destroy", libgtk3.}
diff --git a/src/nigui/private/gtk3/platform_impl.nim b/src/nigui/private/gtk3/platform_impl.nim
index 0d0c420..09db57c 100755
--- a/src/nigui/private/gtk3/platform_impl.nim
+++ b/src/nigui/private/gtk3/platform_impl.nim
@@ -468,10 +468,10 @@ method setPixel(canvas: Canvas, x, y: int, color: Color) =
       raiseError("Pixel is out of range.")
     cairo_surface_flush(canvasImpl.fSurface)
     let i = y * canvasImpl.fStride + x * 4
-    canvasImpl.fData[i + 0] = color.blue.chr
-    canvasImpl.fData[i + 1] = color.green.chr
-    canvasImpl.fData[i + 2] = color.red.chr
-    canvasImpl.fData[i + 3] = 255.chr
+    canvasImpl.fData[i + 0] = color.blue
+    canvasImpl.fData[i + 1] = color.green
+    canvasImpl.fData[i + 2] = color.red
+    canvasImpl.fData[i + 3] = 255
     cairo_surface_mark_dirty(canvasImpl.fSurface)
 
 method `fontFamily=`(canvas: CanvasImpl, fontFamily: string) =
@@ -555,6 +555,14 @@ method saveToJpegFile(image: Image, filePath: string, quality = 80) =
   if not gdk_pixbuf_save(pixbuf, filePath, "jpeg", error.addr, "quality", $quality, nil):
     pRaiseGError(error)
 
+method beginPixelDataAccess(image: Image): ptr UncheckedArray[byte] =
+  let canvas = cast[CanvasImpl](image.canvas)
+  result = canvas.fData
+
+method endPixelDataAccess(image: Image) =
+  let canvas = cast[CanvasImpl](image.canvas)
+  cairo_surface_mark_dirty(canvas.fSurface)
+
 
 # ----------------------------------------------------------------------------------------
 #                                        Window
diff --git a/src/nigui/private/gtk3/platform_types1.nim b/src/nigui/private/gtk3/platform_types1.nim
index d0178cd..505013b 100755
--- a/src/nigui/private/gtk3/platform_types1.nim
+++ b/src/nigui/private/gtk3/platform_types1.nim
@@ -17,7 +17,7 @@ type
 
   CanvasImpl* = ref object of Canvas
     fSurface: pointer
-    fData: cstring
+    fData: ptr UncheckedArray[byte]
     fStride: int
     fCairoContext: pointer
     fFont: pointer
diff --git a/src/nigui/private/windows/platform_impl.nim b/src/nigui/private/windows/platform_impl.nim
index 4ca99bc..052b482 100755
--- a/src/nigui/private/windows/platform_impl.nim
+++ b/src/nigui/private/windows/platform_impl.nim
@@ -708,6 +708,24 @@ method saveToJpegFile(image: Image, filePath: string, quality = 80) =
   # TODO: pass quality
   pCheckGdiplusStatus(GdipSaveImageToFile(canvas.fBitmap, filePath.pUtf8ToUtf16(), clsidEncoder.addr, nil), false)
 
+method beginPixelDataAccess(image: Image): ptr UncheckedArray[byte] =
+  let imageImpl = cast[ImageImpl](image)
+  let canvas = cast[CanvasImpl](image.canvas)
+  var rect: Rect
+  rect.left = 0
+  rect.top = 0
+  rect.right = image.width.int32
+  rect.bottom = image.height.int32
+  pCheckGdiplusStatus(GdipBitmapLockBits(canvas.fBitmap, rect, ImageLockModeWrite, PixelFormat32bppARGB, imageImpl.bitmapDataLockBits))
+  result = imageImpl.bitmapDataLockBits.Scan0
+
+method endPixelDataAccess(image: Image) =
+  let imageImpl = cast[ImageImpl](image)
+  let canvas = cast[CanvasImpl](image.canvas)
+  pCheckGdiplusStatus(GdipBitmapUnlockBits(canvas.fBitmap, imageImpl.bitmapDataLockBits))
+
+
+
 
 # ----------------------------------------------------------------------------------------
 #                                        Window
diff --git a/src/nigui/private/windows/platform_types1.nim b/src/nigui/private/windows/platform_types1.nim
index ddf36cf..52470d4 100755
--- a/src/nigui/private/windows/platform_types1.nim
+++ b/src/nigui/private/windows/platform_types1.nim
@@ -1,3 +1,5 @@
+import windows
+
 # NiGui - Win32 platform-specific code - part 1
 
 # This file will be included in "nigui.nim".
@@ -21,3 +23,4 @@ type
     fAreaBrush: pointer
 
   ImageImpl* = ref object of Image
+    bitmapDataLockBits: BitmapData
diff --git a/src/nigui/private/windows/windows.nim b/src/nigui/private/windows/windows.nim
index ea0bef2..473b727 100755
--- a/src/nigui/private/windows/windows.nim
+++ b/src/nigui/private/windows/windows.nim
@@ -163,6 +163,9 @@ const
   # UnitDocument* = 5
   # UnitMillimeter* = 6
   GMEM_MOVEABLE* = 2
+  PixelFormat32bppARGB* = 2498570
+  ImageLockModeWrite* = 2
+
 
 
 # ----------------------------------------------------------------------------------------
@@ -285,12 +288,20 @@ type
     # dwReserved: int32
     # FlagsEx*: int32
 
-  GUID * = object
+  GUID* = object
     Data1*: int32
     Data2*: int32
     Data3*: int32
     Data4*: int32
 
+  BitmapData* = object
+    Width*: int32
+    Height*: int32
+    Stride*: int32
+    PixelFormat*: int32
+    Scan0*: ptr UncheckedArray[byte]
+    Reserved: pointer
+
 
 # ----------------------------------------------------------------------------------------
 #                               Replacement for Windows Macros
@@ -463,6 +474,8 @@ proc GdipCreateFont*(fontFamily: pointer, emSize: cfloat, style, unit: int32, fo
 proc GdipDeleteFont*(font: pointer): int32 {.importc: "GdipDeleteFont", libGdiplus.}
 proc GdipCreateFontFamilyFromName*(name: cstring, fontCollection: pointer, fontFamily: var pointer): int32 {.importc: "GdipCreateFontFamilyFromName", libGdiplus.}
 proc GdipDeleteFontFamily*(fontFamily: pointer): int32 {.importc: "GdipDeleteFontFamily", libGdiplus.}
+proc GdipBitmapLockBits*(bitmap: pointer, rect: var Rect, flags: int32, format: int32, lockedBitmapData: var BitmapData): int32 {.importc: "GdipBitmapLockBits", libGdiplus.}
+proc GdipBitmapUnlockBits*(bitmap: pointer, lockedBitmapData: var BitmapData): int32 {.importc: "GdipBitmapUnlockBits", libGdiplus.}
 
 
 # ----------------------------------------------------------------------------------------