simpler line width calculation

configure.ac

@@ -28,7 +28,7 @@ AS_IF([test "x$orig_CFLAGS" = "x"], [
         AX_APPEND_LINK_FLAGS(["-flto"])
     ])
     m4_foreach([SCROT_FLAG],
-        [["-O3"], ["-Wall"], ["-Wextra"], ["-Wpedantic"], ["-fno-math-errno"]], [
+        [["-O3"], ["-Wall"], ["-Wextra"], ["-Wpedantic"]], [
             AX_APPEND_COMPILE_FLAGS(["SCROT_FLAG"])
             AS_IF([test "x$LTO_ENABLED" = "xyes"], [
                 AX_APPEND_LINK_FLAGS(["SCROT_FLAG"])

deps.pc

@@ -2,5 +2,4 @@ Name: scrot's mandatory dependencies
 Description: ditto
 Version: infinite
 Cflags: -D_XOPEN_SOURCE=700L
-Libs: -lm
 Requires: x11 imlib2 >= 1.11.0 xcomposite >= 0.2.0 xext xfixes >= 5.0.1 xinerama >= 1.1.3

man/scrot.txt

@@ -175,7 +175,7 @@ SELECTION STYLE
 
   Without the -l option, a default style is used:
 
-    mode=auto,style=solid,width=$dpi/75,opacity=100
+    mode=auto,style=solid,width=...,opacity=100   # FIXME: width
 
   Example:
 

src/scrot_selection.c

@@ -35,7 +35,6 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <err.h>
 #include <errno.h>
-#include <math.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -425,11 +424,8 @@ Imlib_Image scrotSelectionSelectMode(void)
     }
 
     if (opt.lineWidth == 0) {
-        double mmToInches = 1 / 25.4;
-        double inchesDiag = hypot(scr->mwidth, scr->mheight) * mmToInches;
-        double pixelsDiag = hypot(scr->width, scr->height);
-        double dpi = round(pixelsDiag / inchesDiag);
-        opt.lineWidth = fmin(fmax(round(dpi / 75.0), 1), 8);
+        int width = (scr->height + scr->width) / (scr->mheight + scr->mwidth);
+        opt.lineWidth = MIN(MAX(width/4, 1), 8);
     }
 
     if (opt.delaySelection)

src/util.h

@@ -43,6 +43,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #define ARRAY_COUNT(X)   (sizeof(X) / sizeof(0[X]))
 #define MAX(A, B)        ((A) > (B) ? (A) : (B))
+#define MIN(A, B)        ((A) < (B) ? (A) : (B))
 
 typedef struct {
     char *buf;