iv

@@ -1,5 +1,5 @@

 iv : main.o

-	cc -O2 -o iv main.o -lSDL2 -lSDL2_image

+	cc -O2 -o iv main.o -lSDL2 -lSDL2_image -lm

 main.o : main.c

 	cc -O2 -c -Wall main.c

@@ -1,6 +1,7 @@

 /* iv/main.c - see README */

 #include <libgen.h>

+#include <math.h>

 #include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

@@ -241,6 +242,8 @@ int main(int argc, char** argv) {

     unsigned int wdim[2] = {iw, ih};

     /* mouse position */

     int mpos[2];

+    int iic;

+    float dz;

     while (r) {

         ef = 0;

@@ -248,7 +251,7 @@ int main(int argc, char** argv) {

             switch (ev.type) {

                 case SDL_KEYUP:

-                    int iic = 0;

+                    iic = 0;

                     switch (handlekey(ev.key.keysym.sym, &sl[ci], ci, fc, wdim)) {

                         case 4:

                             r = 0;

@@ -286,17 +289,21 @@ int main(int argc, char** argv) {

                 case SDL_MOUSEMOTION:

                     /* pan-dragging if mouse is down */

                     if (SDL_GetMouseState(NULL, NULL) & SDL_BUTTON(1)) {

-                        int hid, big;

+                        int hid, rhid;

                         int rel[2] = {ev.motion.xrel, ev.motion.yrel};

                         /* clamp panning to edges of window */

                         TWICE(

+                            /* scaled (onscreen) image size, halved */

                             hid = ZSH(sl[ci].idim[j], sl[ci].zoom - 1.0);

-                            big = 2 * hid > wdim[j];

+                            rhid = wdim[j] - hid;

+                            if (2 * hid > wdim[j]) {

+                                int tmp = hid;

+                                hid = rhid;

+                                rhid = tmp;

+                            }

                             sl[ci].pan[j] = CLAMP(

-                                big ? wdim[j] - hid : hid,

-                                sl[ci].pan[j] + rel[j],

-                                big ? hid : wdim[j] - hid

-                            )

+                                hid, sl[ci].pan[j] + rel[j], rhid

+                            );

                         )

                         ef = 1;

                     }

@@ -306,7 +313,7 @@ int main(int argc, char** argv) {

                 case SDL_MOUSEWHEEL:

                     /* scrolling changes zoom */

-                    float dz = DZDS * ev.wheel.y;

+                    dz = DZDS * ev.wheel.y;

                     sl[ci].zoom += dz;

                     TWICE(sl[ci].pan[j] = mpos[j] - ZSH((mpos[j] - sl[ci].pan[j]), dz))

                     ef = 1;