Add support for different interpolation modes for drawImage()

2 files changed, 15 insertions, 0 deletions

diff --git a/src/nigui/private/windows/platform_impl.nim b/src/nigui/private/windows/platform_impl.nim
index bdba314..4c6b8d5 100755
--- a/src/nigui/private/windows/platform_impl.nim
+++ b/src/nigui/private/windows/platform_impl.nim
@@ -748,6 +748,17 @@ method getTextLineWidth(canvas: CanvasImpl, text: string): int = canvas.pGetText
 
 method getTextLineHeight(canvas: CanvasImpl): int = canvas.pGetTextSize("a").cy
 
+method `interpolationMode=`(canvas: CanvasImpl, mode: InterpolationMode) =
+  procCall canvas.Canvas.`interpolationMode=`(mode)
+  if canvas.fGraphics == nil:
+    raiseError("Canvas is not in drawing state.")
+  let nativeMode =
+    case mode:
+      of InterpolationMode_Default:         windows.InterpolationMode_Default
+      of InterpolationMode_NearestNeighbor: windows.InterpolationMode_NearestNeighbor
+      of InterpolationMode_Bilinear:        windows.InterpolationMode_Bilinear
+  pCheckGdiplusStatus(GdipSetInterpolationMode(canvas.fGraphics, nativeMode.int32))
+
 
 # ----------------------------------------------------------------------------------------
 #                                        Image
diff --git a/src/nigui/private/windows/windows.nim b/src/nigui/private/windows/windows.nim
index e7e1be9..6ab983e 100755
--- a/src/nigui/private/windows/windows.nim
+++ b/src/nigui/private/windows/windows.nim
@@ -75,6 +75,9 @@ const
   ICON_BIG* = 1
   IDC_ARROW* = 32512
   INVALID_HANDLE_VALUE* = cast[pointer](-1)
+  InterpolationMode_Default* = 0
+  InterpolationMode_Bilinear* = 3
+  InterpolationMode_NearestNeighbor* = 5
   IMAGE_BITMAP* = 0
   IMAGE_ICON* = 1
   # LR_LOADFROMFILE* = 16
@@ -542,6 +545,7 @@ proc GdipDeleteFontFamily*(fontFamily: pointer): int32 {.importc, libGdiplus.}
 proc GdipBitmapLockBits*(bitmap: pointer, rect: var Rect, flags: int32, format: int32, lockedBitmapData: var BitmapData): int32 {.importc, libGdiplus.}
 proc GdipBitmapUnlockBits*(bitmap: pointer, lockedBitmapData: var BitmapData): int32 {.importc, libGdiplus.}
 proc GdipSetTextRenderingHint*(graphics: pointer, mode: int32): int32 {.importc, libGdiplus.}
+proc GdipSetInterpolationMode*(graphics: pointer, interpolationMode: int32): int32 {.importc, libGdiplus.}
 
 
 # ----------------------------------------------------------------------------------------