Merge pull request #2677 from uploadcare/fast-merge

Fast merge()

PIL/Image.py

@@ -2636,11 +2636,9 @@ def merge(mode, bands):
             raise ValueError("mode mismatch")
         if im.size != bands[0].size:
             raise ValueError("size mismatch")
-    im = core.new(mode, bands[0].size)
-    for i in range(getmodebands(mode)):
-        bands[i].load()
-        im.putband(bands[i].im, i)
-    return bands[0]._new(im)
+    for band in bands:
+        band.load()
+    return bands[0]._new(core.merge(mode, *[b.im for b in bands]))
 
 
 # --------------------------------------------------------------------

_imaging.c

@@ -1888,6 +1888,29 @@ _putband(ImagingObject* self, PyObject* args)
     return Py_None;
 }
 
+static PyObject*
+_merge(PyObject* self, PyObject* args)
+{
+    char* mode;
+    ImagingObject *band0 = NULL;
+    ImagingObject *band1 = NULL;
+    ImagingObject *band2 = NULL;
+    ImagingObject *band3 = NULL;
+    Imaging bands[4] = {NULL, NULL, NULL, NULL};
+
+    if (!PyArg_ParseTuple(args, "sO!|O!O!O!", &mode,
+                          &Imaging_Type, &band0, &Imaging_Type, &band1,
+                          &Imaging_Type, &band2, &Imaging_Type, &band3))
+        return NULL;
+
+    if (band0) bands[0] = band0->image;
+    if (band1) bands[1] = band1->image;
+    if (band2) bands[2] = band2->image;
+    if (band3) bands[3] = band3->image;
+
+    return PyImagingNew(ImagingMerge(mode, bands));
+}
+
 static PyObject*
 _split(ImagingObject* self, PyObject* args)
 {
@@ -3325,6 +3348,7 @@ static PyMethodDef functions[] = {
     {"blend", (PyCFunction)_blend, 1},
     {"fill", (PyCFunction)_fill, 1},
     {"new", (PyCFunction)_new, 1},
+    {"merge", (PyCFunction)_merge, 1},
 
     {"getcount", (PyCFunction)_getcount, 1},
 

libImaging/Bands.c

@@ -23,9 +23,9 @@
 
 
 #ifdef WORDS_BIGENDIAN
-    #define MAKE_UINT32(u0, u1, u2, u3) (u3 | (u2<<8)  | (u1<<16)  | (u0<<24))
+    #define MAKE_UINT32(u0, u1, u2, u3) (u3 | (u2<<8) | (u1<<16) | (u0<<24))
 #else
-    #define MAKE_UINT32(u0, u1, u2, u3) (u0 | (u1<<8)  | (u2<<16)  | (u3<<24))
+    #define MAKE_UINT32(u0, u1, u2, u3) (u0 | (u1<<8) | (u2<<16) | (u3<<24))
 #endif
 
 
@@ -234,3 +234,77 @@ ImagingFillBand(Imaging imOut, int band, int color)
 
     return imOut;
 }
+
+Imaging
+ImagingMerge(const char* mode, Imaging bands[4])
+{
+    int i, x, y;
+    int bandsCount = 0;
+    Imaging imOut;
+    Imaging firstBand;
+
+    firstBand = bands[0];
+    if ( ! firstBand) {
+        return (Imaging) ImagingError_ValueError("wrong number of bands");
+    }
+
+    for (i = 0; i < 4; ++i) {
+        if ( ! bands[i]) {
+            break;
+        }
+        if (bands[i]->bands != 1) {
+            return (Imaging) ImagingError_ModeError();
+        }
+        if (bands[i]->xsize != firstBand->xsize
+            || bands[i]->ysize != firstBand->ysize) {
+            return (Imaging) ImagingError_Mismatch();
+        }
+    }
+    bandsCount = i;
+
+    imOut = ImagingNewDirty(mode, firstBand->xsize, firstBand->ysize);
+    if ( ! imOut)
+        return NULL;
+
+    if (imOut->bands != bandsCount) {
+        ImagingDelete(imOut);
+        return (Imaging) ImagingError_ValueError("wrong number of bands");
+    }
+
+    if (imOut->bands == 1)
+        return ImagingCopy2(imOut, firstBand);
+
+    if (imOut->bands == 2) {
+        for (y = 0; y < imOut->ysize; y++) {
+            UINT8* in0 = bands[0]->image8[y];
+            UINT8* in1 = bands[1]->image8[y];
+            UINT32* out = (UINT32*) imOut->image32[y];
+            for (x = 0; x < imOut->xsize; x++) {
+                out[x] = MAKE_UINT32(in0[x], 0, 0, in1[x]);
+            }
+        }
+    } else if (imOut->bands == 3) {
+        for (y = 0; y < imOut->ysize; y++) {
+            UINT8* in0 = bands[0]->image8[y];
+            UINT8* in1 = bands[1]->image8[y];
+            UINT8* in2 = bands[2]->image8[y];
+            UINT32* out = (UINT32*) imOut->image32[y];
+            for (x = 0; x < imOut->xsize; x++) {
+                out[x] = MAKE_UINT32(in0[x], in1[x], in2[x], 0);
+            }
+        }
+    } else if (imOut->bands == 4) {
+        for (y = 0; y < imOut->ysize; y++) {
+            UINT8* in0 = bands[0]->image8[y];
+            UINT8* in1 = bands[1]->image8[y];
+            UINT8* in2 = bands[2]->image8[y];
+            UINT8* in3 = bands[3]->image8[y];
+            UINT32* out = (UINT32*) imOut->image32[y];
+            for (x = 0; x < imOut->xsize; x++) {
+                out[x] = MAKE_UINT32(in0[x], in1[x], in2[x], in3[x]);
+            }
+        }
+    }
+
+    return imOut;
+}

libImaging/Imaging.h

@@ -266,6 +266,7 @@ extern Imaging ImagingFlipTopBottom(Imaging imOut, Imaging imIn);
 extern Imaging ImagingGaussianBlur(Imaging imOut, Imaging imIn, float radius,
     int passes);
 extern Imaging ImagingGetBand(Imaging im, int band);
+extern Imaging ImagingMerge(const char* mode, Imaging bands[4]);
 extern int ImagingSplit(Imaging im, Imaging bands[4]);
 extern int ImagingGetBBox(Imaging im, int bbox[4]);
 typedef struct { int x, y; INT32 count; INT32 pixel; } ImagingColorItem;