Patch by Diederik for 168384. Tested by myself and others and works well, additionall...

diff --git a/src/libnr/nr-compose-transform.cpp b/src/libnr/nr-compose-transform.cpp
index afc8fd987b40d0dc9c4bde8cb2c1d98be5892d48..ee12edba99d2a8d9e89225353f9de523d488a116 100644 (file)
--- a/src/libnr/nr-compose-transform.cpp
+++ b/src/libnr/nr-compose-transform.cpp
@@ -40,6 +40,7 @@ void nr_mmx_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_n (unsigned char *px, int
 
 /* Fixed point precision */
 #define FBITS 12
+#define FBITS_HP 18 // In some places we need a higher precision
 
 void nr_R8G8B8A8_N_EMPTY_R8G8B8A8_N_TRANSFORM (unsigned char *px, int w, int h, int rs,
                                               const unsigned char *spx, int sw, int sh, int srs,
@@ -168,10 +169,10 @@ void nr_R8G8B8A8_N_R8G8B8A8_N_R8G8B8A8_P_TRANSFORM (unsigned char *px, int w, in
 static void
 nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_0 (unsigned char *px, int w, int h, int rs,
                                                 const unsigned char *spx, int sw, int sh, int srs,
-                                                const long *FFd2s, unsigned int alpha)
+                                                const long long *FFd2s, unsigned int alpha)
 {
-       unsigned char *d0;
-       int FFsx0, FFsy0;
+    unsigned char *d0;
+       long long FFsx0, FFsy0;
        int x, y;
 
        d0 = px;
@@ -180,15 +181,15 @@ nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_0 (unsigned char *px, int w, int h
 
        for (y = 0; y < h; y++) {
                unsigned char *d;
-               long FFsx, FFsy;
+               long long FFsx, FFsy;
                d = d0;
                FFsx = FFsx0;
                FFsy = FFsy0;
                for (x = 0; x < w; x++) {
                        long sx, sy;
-                       sx = FFsx >> FBITS;
+                       sx = long(FFsx >> FBITS_HP);
                        if ((sx >= 0) && (sx < sw)) {
-                               sy = FFsy >> FBITS;
+                               sy = long(FFsy >> FBITS_HP);
                                if ((sy >= 0) && (sy < sh)) {
                                        const unsigned char *s;
                                        unsigned int a;
@@ -224,11 +225,11 @@ nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_0 (unsigned char *px, int w, int h
 static void
 nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_n (unsigned char *px, int w, int h, int rs,
                                                 const unsigned char *spx, int sw, int sh, int srs,
-                                                const long *FFd2s, const long *FF_S, unsigned int alpha, int dbits)
+                                                const long long *FFd2s, const long *FF_S, unsigned int alpha, int dbits)
 {
        int size;
        unsigned char *d0;
-       int FFsx0, FFsy0;
+       long long FFsx0, FFsy0;
        int x, y;
 
        size = (1 << dbits);
@@ -242,7 +243,7 @@ nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_n (unsigned char *px, int w, int h
 
        for (y = 0; y < h; y++) {
                unsigned char *d;
-               long FFsx, FFsy;
+               long long FFsx, FFsy;
                d = d0;
                FFsx = FFsx0;
                FFsy = FFsy0;
@@ -252,9 +253,9 @@ nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_n (unsigned char *px, int w, int h
                        r = g = b = a = 0;
                        for (i = 0; i < size; i++) {
                                long sx, sy;
-                               sx = (FFsx + FF_S[2 * i]) >> FBITS;
+                               sx = (FFsx >> FBITS_HP) + (FF_S[2 * i] >> FBITS);
                                if ((sx >= 0) && (sx < sw)) {
-                                       sy = (FFsy + FF_S[2 * i + 1]) >> FBITS;
+                                       sy = (FFsy >> FBITS_HP) + (FF_S[2 * i + 1] >> FBITS);
                                        if ((sy >= 0) && (sy < sh)) {
                                                const unsigned char *s;
                                                unsigned int ca;
@@ -302,6 +303,7 @@ void nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM (unsigned char *px, int w, in
 {
        int dbits;
        long FFd2s[6];
+       long long FFd2s_HP[6]; // with higher precision
        int i;
 
        if (alpha == 0) return;
@@ -310,6 +312,7 @@ void nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM (unsigned char *px, int w, in
 
        for (i = 0; i < 6; i++) {
                FFd2s[i] = (long) (d2s[i] * (1 << FBITS) + 0.5);
+               FFd2s_HP[i] = (long long) (d2s[i] * (1 << FBITS_HP) + 0.5);;
        }
 
        if (dbits == 0) {
@@ -320,7 +323,7 @@ void nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM (unsigned char *px, int w, in
                        return;
                }
 #endif
-               nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_0 (px, w, h, rs, spx, sw, sh, srs, FFd2s, alpha);
+               nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_0 (px, w, h, rs, spx, sw, sh, srs, FFd2s_HP, alpha);
        } else {
                int xsize, ysize;
                long FFs_x_x_S, FFs_x_y_S, FFs_y_x_S, FFs_y_y_S;
@@ -351,7 +354,7 @@ void nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM (unsigned char *px, int w, in
                        return;
                }
 #endif
-               nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_n (px, w, h, rs, spx, sw, sh, srs, FFd2s, FF_S, alpha, dbits);
+               nr_R8G8B8A8_P_R8G8B8A8_P_R8G8B8A8_N_TRANSFORM_n (px, w, h, rs, spx, sw, sh, srs, FFd2s_HP, FF_S, alpha, dbits);
        }
 }