[MSPAINT] Implement skew (#4362)

- Add SkewDIB helper function in dib.cpp.
- Implement Stretch and Skew feature by SelectionModel::StretchSkew and ImageModel::StretchSkew.
- Move ColorKeyedMaskBlt function.
CORE-16634

base/applications/mspaint/dib.cpp

@@ -9,6 +9,7 @@
 /* INCLUDES *********************************************************/
 
 #include "precomp.h"
+#include <math.h>
 
 /* FUNCTIONS ********************************************************/
 
@@ -243,3 +244,58 @@ HBITMAP Rotate90DegreeBlt(HDC hDC1, INT cx, INT cy, BOOL bRight)
     DeleteDC(hDC2);
     return hbm2;
 }
+
+#ifndef M_PI
+    #define M_PI 3.14159265
+#endif
+
+HBITMAP SkewDIB(HDC hDC1, HBITMAP hbm, INT nDegree, BOOL bVertical)
+{
+    if (nDegree == 0)
+        return CopyDIBImage(hbm);
+
+    const double eTan = tan(abs(nDegree) * M_PI / 180);
+
+    BITMAP bm;
+    GetObjectW(hbm, sizeof(bm), &bm);
+    INT cx = bm.bmWidth, cy = bm.bmHeight, dx = 0, dy = 0;
+    if (bVertical)
+        dy = INT(cx * eTan);
+    else
+        dx = INT(cy * eTan);
+
+    if (dx == 0 && dy == 0)
+        return CopyDIBImage(hbm);
+
+    HBITMAP hbmNew = CreateColorDIB(cx + dx, cy + dy, RGB(255, 255, 255));
+    if (!hbmNew)
+        return NULL;
+
+    HDC hDC2 = CreateCompatibleDC(NULL);
+    HGDIOBJ hbm2Old = SelectObject(hDC2, hbmNew);
+    if (bVertical)
+    {
+        for (INT x = 0; x < cx; ++x)
+        {
+            INT delta = INT(x * eTan);
+            if (nDegree > 0)
+                BitBlt(hDC2, x, (dy - delta), 1, cy, hDC1, x, 0, SRCCOPY);
+            else
+                BitBlt(hDC2, x, delta, 1, cy, hDC1, x, 0, SRCCOPY);
+        }
+    }
+    else
+    {
+        for (INT y = 0; y < cy; ++y)
+        {
+            INT delta = INT(y * eTan);
+            if (nDegree > 0)
+                BitBlt(hDC2, (dx - delta), y, cx, 1, hDC1, 0, y, SRCCOPY);
+            else
+                BitBlt(hDC2, delta, y, cx, 1, hDC1, 0, y, SRCCOPY);
+        }
+    }
+    SelectObject(hDC2, hbm2Old);
+    DeleteDC(hDC2);
+    return hbmNew;
+}