Made clock position freely modifiable

i3lock.c

@@ -85,6 +85,8 @@ char time_format[32] = "%H:%M:%S\0";
 char date_format[32] = "%A, %m %Y\0";
 char time_font[32] = "sans-serif\0";
 char date_font[32] = "sans-serif\0";
+char clock_x_expr[32] = "ix\0";
+char clock_y_expr[32] = "iy+20\0";
 
 /* opts for blurring */
 bool blur = false;
@@ -905,6 +907,7 @@ int main(int argc, char *argv[]) {
         {"datestr", required_argument, NULL, 0},
         {"timefont", required_argument, NULL, 0},
         {"datefont", required_argument, NULL, 0},
+        {"clockpos", required_argument, NULL, 0},
 
         {"blur", required_argument, NULL, 'B'},
 
@@ -1143,6 +1146,17 @@ int main(int argc, char *argv[]) {
                     }
                     strcpy(date_font,optarg);
                 }
+                else if (strcmp(longopts[optind].name, "clockpos") == 0) {
+                    //read in to clock_x_expr and clock_y_expr
+                    if (strlen(optarg) > 31) {
+                        // this is overly restrictive since both the x and y string buffers have size 32, but it's easier to check.
+                        errx(1, "date position string can be at most 31 characters");
+                    }
+                    char* arg = optarg;
+                    if (sscanf(arg, "%30[^:]:%30[^:]", &clock_x_expr, &clock_y_expr) != 2) {
+                        errx(1, "clockpos must be of the form x:y");
+                    }
+                }
                 break;
             case 'f':
                 show_failed_attempts = true;

tinyexpr.c

@@ -0,0 +1,653 @@
+/*
+ * TINYEXPR - Tiny recursive descent parser and evaluation engine in C
+ *
+ * Copyright (c) 2015, 2016 Lewis Van Winkle
+ *
+ * http://CodePlea.com
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgement in the product documentation would be
+ * appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+/* COMPILE TIME OPTIONS */
+
+/* Exponentiation associativity:
+For a^b^c = (a^b)^c and -a^b = (-a)^b do nothing.
+For a^b^c = a^(b^c) and -a^b = -(a^b) uncomment the next line.*/
+/* #define TE_POW_FROM_RIGHT */
+
+/* Logarithms
+For log = base 10 log do nothing
+For log = natural log uncomment the next line. */
+/* #define TE_NAT_LOG */
+
+#include "tinyexpr.h"
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+#include <stdio.h>
+#include <limits.h>
+
+#ifndef NAN
+#define NAN (0.0/0.0)
+#endif
+
+#ifndef INFINITY
+#define INFINITY (1.0/0.0)
+#endif
+
+
+typedef double (*te_fun2)(double, double);
+
+enum {
+    TOK_NULL = TE_CLOSURE7+1, TOK_ERROR, TOK_END, TOK_SEP,
+    TOK_OPEN, TOK_CLOSE, TOK_NUMBER, TOK_VARIABLE, TOK_INFIX
+};
+
+
+enum {TE_CONSTANT = 1};
+
+
+typedef struct state {
+    const char *start;
+    const char *next;
+    int type;
+    union {double value; const double *bound; const void *function;};
+    void *context;
+
+    const te_variable *lookup;
+    int lookup_len;
+} state;
+
+
+#define TYPE_MASK(TYPE) ((TYPE)&0x0000001F)
+
+#define IS_PURE(TYPE) (((TYPE) & TE_FLAG_PURE) != 0)
+#define IS_FUNCTION(TYPE) (((TYPE) & TE_FUNCTION0) != 0)
+#define IS_CLOSURE(TYPE) (((TYPE) & TE_CLOSURE0) != 0)
+#define ARITY(TYPE) ( ((TYPE) & (TE_FUNCTION0 | TE_CLOSURE0)) ? ((TYPE) & 0x00000007) : 0 )
+#define NEW_EXPR(type, ...) new_expr((type), (const te_expr*[]){__VA_ARGS__})
+
+static te_expr *new_expr(const int type, const te_expr *parameters[]) {
+    const int arity = ARITY(type);
+    const int psize = sizeof(void*) * arity;
+    const int size = (sizeof(te_expr) - sizeof(void*)) + psize + (IS_CLOSURE(type) ? sizeof(void*) : 0);
+    te_expr *ret = malloc(size);
+    memset(ret, 0, size);
+    if (arity && parameters) {
+        memcpy(ret->parameters, parameters, psize);
+    }
+    ret->type = type;
+    ret->bound = 0;
+    return ret;
+}
+
+
+void te_free_parameters(te_expr *n) {
+    if (!n) return;
+    switch (TYPE_MASK(n->type)) {
+        case TE_FUNCTION7: case TE_CLOSURE7: te_free(n->parameters[6]);
+        case TE_FUNCTION6: case TE_CLOSURE6: te_free(n->parameters[5]);
+        case TE_FUNCTION5: case TE_CLOSURE5: te_free(n->parameters[4]);
+        case TE_FUNCTION4: case TE_CLOSURE4: te_free(n->parameters[3]);
+        case TE_FUNCTION3: case TE_CLOSURE3: te_free(n->parameters[2]);
+        case TE_FUNCTION2: case TE_CLOSURE2: te_free(n->parameters[1]);
+        case TE_FUNCTION1: case TE_CLOSURE1: te_free(n->parameters[0]);
+    }
+}
+
+
+void te_free(te_expr *n) {
+    if (!n) return;
+    te_free_parameters(n);
+    free(n);
+}
+
+
+static double pi() {return 3.14159265358979323846;}
+static double e() {return 2.71828182845904523536;}
+static double fac(double a) {/* simplest version of fac */
+    if (a < 0.0)
+        return NAN;
+    if (a > UINT_MAX)
+        return INFINITY;
+    unsigned int ua = (unsigned int)(a);
+    unsigned long int result = 1, i;
+    for (i = 1; i <= ua; i++) {
+        if (i > ULONG_MAX / result)
+            return INFINITY;
+        result *= i;
+    }
+    return (double)result;
+}
+static double ncr(double n, double r) {
+    if (n < 0.0 || r < 0.0 || n < r) return NAN;
+    if (n > UINT_MAX || r > UINT_MAX) return INFINITY;
+    unsigned long int un = (unsigned int)(n), ur = (unsigned int)(r), i;
+    unsigned long int result = 1;
+    if (ur > un / 2) ur = un - ur;
+    for (i = 1; i <= ur; i++) {
+        if (result > ULONG_MAX / (un - ur + i))
+            return INFINITY;
+        result *= un - ur + i;
+        result /= i;
+    }
+    return result;
+}
+static double npr(double n, double r) {return ncr(n, r) * fac(r);}
+
+static const te_variable functions[] = {
+    /* must be in alphabetical order */
+    {"abs", fabs,     TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"acos", acos,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"asin", asin,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"atan", atan,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"atan2", atan2,  TE_FUNCTION2 | TE_FLAG_PURE, 0},
+    {"ceil", ceil,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"cos", cos,      TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"cosh", cosh,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"e", e,          TE_FUNCTION0 | TE_FLAG_PURE, 0},
+    {"exp", exp,      TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"fac", fac,      TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"floor", floor,  TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"ln", log,       TE_FUNCTION1 | TE_FLAG_PURE, 0},
+#ifdef TE_NAT_LOG
+    {"log", log,      TE_FUNCTION1 | TE_FLAG_PURE, 0},
+#else
+    {"log", log10,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+#endif
+    {"log10", log10,  TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"ncr", ncr,      TE_FUNCTION2 | TE_FLAG_PURE, 0},
+    {"npr", npr,      TE_FUNCTION2 | TE_FLAG_PURE, 0},
+    {"pi", pi,        TE_FUNCTION0 | TE_FLAG_PURE, 0},
+    {"pow", pow,      TE_FUNCTION2 | TE_FLAG_PURE, 0},
+    {"sin", sin,      TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"sinh", sinh,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"sqrt", sqrt,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"tan", tan,      TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {"tanh", tanh,    TE_FUNCTION1 | TE_FLAG_PURE, 0},
+    {0, 0, 0, 0}
+};
+
+static const te_variable *find_builtin(const char *name, int len) {
+    int imin = 0;
+    int imax = sizeof(functions) / sizeof(te_variable) - 2;
+
+    /*Binary search.*/
+    while (imax >= imin) {
+        const int i = (imin + ((imax-imin)/2));
+        int c = strncmp(name, functions[i].name, len);
+        if (!c) c = '\0' - functions[i].name[len];
+        if (c == 0) {
+            return functions + i;
+        } else if (c > 0) {
+            imin = i + 1;
+        } else {
+            imax = i - 1;
+        }
+    }
+
+    return 0;
+}
+
+static const te_variable *find_lookup(const state *s, const char *name, int len) {
+    int iters;
+    const te_variable *var;
+    if (!s->lookup) return 0;
+
+    for (var = s->lookup, iters = s->lookup_len; iters; ++var, --iters) {
+        if (strncmp(name, var->name, len) == 0 && var->name[len] == '\0') {
+            return var;
+        }
+    }
+    return 0;
+}
+
+
+
+static double add(double a, double b) {return a + b;}
+static double sub(double a, double b) {return a - b;}
+static double mul(double a, double b) {return a * b;}
+static double divide(double a, double b) {return a / b;}
+static double negate(double a) {return -a;}
+static double comma(double a, double b) {(void)a; return b;}
+
+
+void next_token(state *s) {
+    s->type = TOK_NULL;
+
+    do {
+
+        if (!*s->next){
+            s->type = TOK_END;
+            return;
+        }
+
+        /* Try reading a number. */
+        if ((s->next[0] >= '0' && s->next[0] <= '9') || s->next[0] == '.') {
+            s->value = strtod(s->next, (char**)&s->next);
+            s->type = TOK_NUMBER;
+        } else {
+            /* Look for a variable or builtin function call. */
+            if (s->next[0] >= 'a' && s->next[0] <= 'z') {
+                const char *start;
+                start = s->next;
+                while ((s->next[0] >= 'a' && s->next[0] <= 'z') || (s->next[0] >= '0' && s->next[0] <= '9') || (s->next[0] == '_')) s->next++;
+
+                const te_variable *var = find_lookup(s, start, s->next - start);
+                if (!var) var = find_builtin(start, s->next - start);
+
+                if (!var) {
+                    s->type = TOK_ERROR;
+                } else {
+                    switch(TYPE_MASK(var->type))
+                    {
+                        case TE_VARIABLE:
+                            s->type = TOK_VARIABLE;
+                            s->bound = var->address;
+                            break;
+
+                        case TE_CLOSURE0: case TE_CLOSURE1: case TE_CLOSURE2: case TE_CLOSURE3:
+                        case TE_CLOSURE4: case TE_CLOSURE5: case TE_CLOSURE6: case TE_CLOSURE7:
+                            s->context = var->context;
+
+                        case TE_FUNCTION0: case TE_FUNCTION1: case TE_FUNCTION2: case TE_FUNCTION3:
+                        case TE_FUNCTION4: case TE_FUNCTION5: case TE_FUNCTION6: case TE_FUNCTION7:
+                            s->type = var->type;
+                            s->function = var->address;
+                            break;
+                    }
+                }
+
+            } else {
+                /* Look for an operator or special character. */
+                switch (s->next++[0]) {
+                    case '+': s->type = TOK_INFIX; s->function = add; break;
+                    case '-': s->type = TOK_INFIX; s->function = sub; break;
+                    case '*': s->type = TOK_INFIX; s->function = mul; break;
+                    case '/': s->type = TOK_INFIX; s->function = divide; break;
+                    case '^': s->type = TOK_INFIX; s->function = pow; break;
+                    case '%': s->type = TOK_INFIX; s->function = fmod; break;
+                    case '(': s->type = TOK_OPEN; break;
+                    case ')': s->type = TOK_CLOSE; break;
+                    case ',': s->type = TOK_SEP; break;
+                    case ' ': case '\t': case '\n': case '\r': break;
+                    default: s->type = TOK_ERROR; break;
+                }
+            }
+        }
+    } while (s->type == TOK_NULL);
+}
+
+
+static te_expr *list(state *s);
+static te_expr *expr(state *s);
+static te_expr *power(state *s);
+
+static te_expr *base(state *s) {
+    /* <base>      =    <constant> | <variable> | <function-0> {"(" ")"} | <function-1> <power> | <function-X> "(" <expr> {"," <expr>} ")" | "(" <list> ")" */
+    te_expr *ret;
+    int arity;
+
+    switch (TYPE_MASK(s->type)) {
+        case TOK_NUMBER:
+            ret = new_expr(TE_CONSTANT, 0);
+            ret->value = s->value;
+            next_token(s);
+            break;
+
+        case TOK_VARIABLE:
+            ret = new_expr(TE_VARIABLE, 0);
+            ret->bound = s->bound;
+            next_token(s);
+            break;
+
+        case TE_FUNCTION0:
+        case TE_CLOSURE0:
+            ret = new_expr(s->type, 0);
+            ret->function = s->function;
+            if (IS_CLOSURE(s->type)) ret->parameters[0] = s->context;
+            next_token(s);
+            if (s->type == TOK_OPEN) {
+                next_token(s);
+                if (s->type != TOK_CLOSE) {
+                    s->type = TOK_ERROR;
+                } else {
+                    next_token(s);
+                }
+            }
+            break;
+
+        case TE_FUNCTION1:
+        case TE_CLOSURE1:
+            ret = new_expr(s->type, 0);
+            ret->function = s->function;
+            if (IS_CLOSURE(s->type)) ret->parameters[1] = s->context;
+            next_token(s);
+            ret->parameters[0] = power(s);
+            break;
+
+        case TE_FUNCTION2: case TE_FUNCTION3: case TE_FUNCTION4:
+        case TE_FUNCTION5: case TE_FUNCTION6: case TE_FUNCTION7:
+        case TE_CLOSURE2: case TE_CLOSURE3: case TE_CLOSURE4:
+        case TE_CLOSURE5: case TE_CLOSURE6: case TE_CLOSURE7:
+            arity = ARITY(s->type);
+
+            ret = new_expr(s->type, 0);
+            ret->function = s->function;
+            if (IS_CLOSURE(s->type)) ret->parameters[arity] = s->context;
+            next_token(s);
+
+            if (s->type != TOK_OPEN) {
+                s->type = TOK_ERROR;
+            } else {
+                int i;
+                for(i = 0; i < arity; i++) {
+                    next_token(s);
+                    ret->parameters[i] = expr(s);
+                    if(s->type != TOK_SEP) {
+                        break;
+                    }
+                }
+                if(s->type != TOK_CLOSE || i != arity - 1) {
+                    s->type = TOK_ERROR;
+                } else {
+                    next_token(s);
+                }
+            }
+
+            break;
+
+        case TOK_OPEN:
+            next_token(s);
+            ret = list(s);
+            if (s->type != TOK_CLOSE) {
+                s->type = TOK_ERROR;
+            } else {
+                next_token(s);
+            }
+            break;
+
+        default:
+            ret = new_expr(0, 0);
+            s->type = TOK_ERROR;
+            ret->value = NAN;
+            break;
+    }
+
+    return ret;
+}
+
+
+static te_expr *power(state *s) {
+    /* <power>     =    {("-" | "+")} <base> */
+    int sign = 1;
+    while (s->type == TOK_INFIX && (s->function == add || s->function == sub)) {
+        if (s->function == sub) sign = -sign;
+        next_token(s);
+    }
+
+    te_expr *ret;
+
+    if (sign == 1) {
+        ret = base(s);
+    } else {
+        ret = NEW_EXPR(TE_FUNCTION1 | TE_FLAG_PURE, base(s));
+        ret->function = negate;
+    }
+
+    return ret;
+}
+
+#ifdef TE_POW_FROM_RIGHT
+static te_expr *factor(state *s) {
+    /* <factor>    =    <power> {"^" <power>} */
+    te_expr *ret = power(s);
+
+    int neg = 0;
+    te_expr *insertion = 0;
+
+    if (ret->type == (TE_FUNCTION1 | TE_FLAG_PURE) && ret->function == negate) {
+        te_expr *se = ret->parameters[0];
+        free(ret);
+        ret = se;
+        neg = 1;
+    }
+
+    while (s->type == TOK_INFIX && (s->function == pow)) {
+        te_fun2 t = s->function;
+        next_token(s);
+
+        if (insertion) {
+            /* Make exponentiation go right-to-left. */
+            te_expr *insert = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, insertion->parameters[1], power(s));
+            insert->function = t;
+            insertion->parameters[1] = insert;
+            insertion = insert;
+        } else {
+            ret = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, ret, power(s));
+            ret->function = t;
+            insertion = ret;
+        }
+    }
+
+    if (neg) {
+        ret = NEW_EXPR(TE_FUNCTION1 | TE_FLAG_PURE, ret);
+        ret->function = negate;
+    }
+
+    return ret;
+}
+#else
+static te_expr *factor(state *s) {
+    /* <factor>    =    <power> {"^" <power>} */
+    te_expr *ret = power(s);
+
+    while (s->type == TOK_INFIX && (s->function == pow)) {
+        te_fun2 t = s->function;
+        next_token(s);
+        ret = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, ret, power(s));
+        ret->function = t;
+    }
+
+    return ret;
+}
+#endif
+
+
+
+static te_expr *term(state *s) {
+    /* <term>      =    <factor> {("*" | "/" | "%") <factor>} */
+    te_expr *ret = factor(s);
+
+    while (s->type == TOK_INFIX && (s->function == mul || s->function == divide || s->function == fmod)) {
+        te_fun2 t = s->function;
+        next_token(s);
+        ret = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, ret, factor(s));
+        ret->function = t;
+    }
+
+    return ret;
+}
+
+
+static te_expr *expr(state *s) {
+    /* <expr>      =    <term> {("+" | "-") <term>} */
+    te_expr *ret = term(s);
+
+    while (s->type == TOK_INFIX && (s->function == add || s->function == sub)) {
+        te_fun2 t = s->function;
+        next_token(s);
+        ret = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, ret, term(s));
+        ret->function = t;
+    }
+
+    return ret;
+}
+
+
+static te_expr *list(state *s) {
+    /* <list>      =    <expr> {"," <expr>} */
+    te_expr *ret = expr(s);
+
+    while (s->type == TOK_SEP) {
+        next_token(s);
+        ret = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, ret, expr(s));
+        ret->function = comma;
+    }
+
+    return ret;
+}
+
+
+#define TE_FUN(...) ((double(*)(__VA_ARGS__))n->function)
+#define M(e) te_eval(n->parameters[e])
+
+
+double te_eval(const te_expr *n) {
+    if (!n) return NAN;
+
+    switch(TYPE_MASK(n->type)) {
+        case TE_CONSTANT: return n->value;
+        case TE_VARIABLE: return *n->bound;
+
+        case TE_FUNCTION0: case TE_FUNCTION1: case TE_FUNCTION2: case TE_FUNCTION3:
+        case TE_FUNCTION4: case TE_FUNCTION5: case TE_FUNCTION6: case TE_FUNCTION7:
+            switch(ARITY(n->type)) {
+                case 0: return TE_FUN(void)();
+                case 1: return TE_FUN(double)(M(0));
+                case 2: return TE_FUN(double, double)(M(0), M(1));
+                case 3: return TE_FUN(double, double, double)(M(0), M(1), M(2));
+                case 4: return TE_FUN(double, double, double, double)(M(0), M(1), M(2), M(3));
+                case 5: return TE_FUN(double, double, double, double, double)(M(0), M(1), M(2), M(3), M(4));
+                case 6: return TE_FUN(double, double, double, double, double, double)(M(0), M(1), M(2), M(3), M(4), M(5));
+                case 7: return TE_FUN(double, double, double, double, double, double, double)(M(0), M(1), M(2), M(3), M(4), M(5), M(6));
+                default: return NAN;
+            }
+
+        case TE_CLOSURE0: case TE_CLOSURE1: case TE_CLOSURE2: case TE_CLOSURE3:
+        case TE_CLOSURE4: case TE_CLOSURE5: case TE_CLOSURE6: case TE_CLOSURE7:
+            switch(ARITY(n->type)) {
+                case 0: return TE_FUN(void*)(n->parameters[0]);
+                case 1: return TE_FUN(void*, double)(n->parameters[1], M(0));
+                case 2: return TE_FUN(void*, double, double)(n->parameters[2], M(0), M(1));
+                case 3: return TE_FUN(void*, double, double, double)(n->parameters[3], M(0), M(1), M(2));
+                case 4: return TE_FUN(void*, double, double, double, double)(n->parameters[4], M(0), M(1), M(2), M(3));
+                case 5: return TE_FUN(void*, double, double, double, double, double)(n->parameters[5], M(0), M(1), M(2), M(3), M(4));
+                case 6: return TE_FUN(void*, double, double, double, double, double, double)(n->parameters[6], M(0), M(1), M(2), M(3), M(4), M(5));
+                case 7: return TE_FUN(void*, double, double, double, double, double, double, double)(n->parameters[7], M(0), M(1), M(2), M(3), M(4), M(5), M(6));
+                default: return NAN;
+            }
+
+        default: return NAN;
+    }
+
+}
+
+#undef TE_FUN
+#undef M
+
+static void optimize(te_expr *n) {
+    /* Evaluates as much as possible. */
+    if (n->type == TE_CONSTANT) return;
+    if (n->type == TE_VARIABLE) return;
+
+    /* Only optimize out functions flagged as pure. */
+    if (IS_PURE(n->type)) {
+        const int arity = ARITY(n->type);
+        int known = 1;
+        int i;
+        for (i = 0; i < arity; ++i) {
+            optimize(n->parameters[i]);
+            if (((te_expr*)(n->parameters[i]))->type != TE_CONSTANT) {
+                known = 0;
+            }
+        }
+        if (known) {
+            const double value = te_eval(n);
+            te_free_parameters(n);
+            n->type = TE_CONSTANT;
+            n->value = value;
+        }
+    }
+}
+
+
+te_expr *te_compile(const char *expression, const te_variable *variables, int var_count, int *error) {
+    state s;
+    s.start = s.next = expression;
+    s.lookup = variables;
+    s.lookup_len = var_count;
+
+    next_token(&s);
+    te_expr *root = list(&s);
+
+    if (s.type != TOK_END) {
+        te_free(root);
+        if (error) {
+            *error = (s.next - s.start);
+            if (*error == 0) *error = 1;
+        }
+        return 0;
+    } else {
+        optimize(root);
+        if (error) *error = 0;
+        return root;
+    }
+}
+
+
+double te_interp(const char *expression, int *error) {
+    te_expr *n = te_compile(expression, 0, 0, error);
+    double ret;
+    if (n) {
+        ret = te_eval(n);
+        te_free(n);
+    } else {
+        ret = NAN;
+    }
+    return ret;
+}
+
+static void pn (const te_expr *n, int depth) {
+    int i, arity;
+    printf("%*s", depth, "");
+
+    switch(TYPE_MASK(n->type)) {
+    case TE_CONSTANT: printf("%f\n", n->value); break;
+    case TE_VARIABLE: printf("bound %p\n", n->bound); break;
+
+    case TE_FUNCTION0: case TE_FUNCTION1: case TE_FUNCTION2: case TE_FUNCTION3:
+    case TE_FUNCTION4: case TE_FUNCTION5: case TE_FUNCTION6: case TE_FUNCTION7:
+    case TE_CLOSURE0: case TE_CLOSURE1: case TE_CLOSURE2: case TE_CLOSURE3:
+    case TE_CLOSURE4: case TE_CLOSURE5: case TE_CLOSURE6: case TE_CLOSURE7:
+         arity = ARITY(n->type);
+         printf("f%d", arity);
+         for(i = 0; i < arity; i++) {
+             printf(" %p", n->parameters[i]);
+         }
+         printf("\n");
+         for(i = 0; i < arity; i++) {
+             pn(n->parameters[i], depth + 1);
+         }
+         break;
+    }
+}
+
+
+void te_print(const te_expr *n) {
+    pn(n, 0);
+}

tinyexpr.h

@@ -0,0 +1,86 @@
+/*
+ * TINYEXPR - Tiny recursive descent parser and evaluation engine in C
+ *
+ * Copyright (c) 2015, 2016 Lewis Van Winkle
+ *
+ * http://CodePlea.com
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgement in the product documentation would be
+ * appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+#ifndef __TINYEXPR_H__
+#define __TINYEXPR_H__
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+
+typedef struct te_expr {
+    int type;
+    union {double value; const double *bound; const void *function;};
+    void *parameters[1];
+} te_expr;
+
+
+enum {
+    TE_VARIABLE = 0,
+
+    TE_FUNCTION0 = 8, TE_FUNCTION1, TE_FUNCTION2, TE_FUNCTION3,
+    TE_FUNCTION4, TE_FUNCTION5, TE_FUNCTION6, TE_FUNCTION7,
+
+    TE_CLOSURE0 = 16, TE_CLOSURE1, TE_CLOSURE2, TE_CLOSURE3,
+    TE_CLOSURE4, TE_CLOSURE5, TE_CLOSURE6, TE_CLOSURE7,
+
+    TE_FLAG_PURE = 32
+};
+
+typedef struct te_variable {
+    const char *name;
+    const void *address;
+    int type;
+    void *context;
+} te_variable;
+
+
+
+/* Parses the input expression, evaluates it, and frees it. */
+/* Returns NaN on error. */
+double te_interp(const char *expression, int *error);
+
+/* Parses the input expression and binds variables. */
+/* Returns NULL on error. */
+te_expr *te_compile(const char *expression, const te_variable *variables, int var_count, int *error);
+
+/* Evaluates the expression. */
+double te_eval(const te_expr *n);
+
+/* Prints debugging information on the syntax tree. */
+void te_print(const te_expr *n);
+
+/* Frees the expression. */
+/* This is safe to call on NULL pointers. */
+void te_free(te_expr *n);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /*__TINYEXPR_H__*/

unlock_indicator.c

@@ -20,6 +20,7 @@
 #include "xcb.h"
 #include "unlock_indicator.h"
 #include "xinerama.h"
+#include "tinyexpr.h"
 
 /* clock stuff */
 #include <time.h>
@@ -28,6 +29,8 @@
 #define BUTTON_SPACE (BUTTON_RADIUS + 5)
 #define BUTTON_CENTER (BUTTON_RADIUS + 5)
 #define BUTTON_DIAMETER (2 * BUTTON_SPACE)
+#define CLOCK_WIDTH 400 
+#define CLOCK_HEIGHT 200 
 
 /*******************************************************************************
  * Variables defined in i3lock.c.
@@ -80,6 +83,8 @@ extern char time_format[32];
 extern char date_format[32];
 extern char time_font[32];
 extern char date_font[32];
+extern char clock_x_expr[32];
+extern char clock_y_expr[32];
 /* Whether the failed attempts should be displayed. */
 extern bool show_failed_attempts;
 /* Number of failed unlock attempts. */
@@ -126,6 +131,8 @@ static double scaling_factor(void) {
 xcb_pixmap_t draw_image(uint32_t *resolution) {
     xcb_pixmap_t bg_pixmap = XCB_NONE;
     int button_diameter_physical = ceil(scaling_factor() * BUTTON_DIAMETER);
+    int clock_width_physical = ceil(scaling_factor() * CLOCK_WIDTH);
+    int clock_height_physical = ceil(scaling_factor() * CLOCK_HEIGHT);
     DEBUG("scaling_factor is %.f, physical diameter is %d px\n",
           scaling_factor(), button_diameter_physical);
 
@@ -134,10 +141,15 @@ xcb_pixmap_t draw_image(uint32_t *resolution) {
     bg_pixmap = create_bg_pixmap(conn, screen, resolution, color);
     /* Initialize cairo: Create one in-memory surface to render the unlock
      * indicator on, create one XCB surface to actually draw (one or more,
-     * depending on the amount of screens) unlock indicators on. */
+     * depending on the amount of screens) unlock indicators on. 
+     * A third surface for the clock display is created as well
+     */
     cairo_surface_t *output = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, button_diameter_physical, button_diameter_physical);
     cairo_t *ctx = cairo_create(output);
 
+    cairo_surface_t *clock_output = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, clock_width_physical, clock_height_physical);
+    cairo_t *clock_ctx = cairo_create(clock_output);
+
     cairo_surface_t *xcb_output = cairo_xcb_surface_create(conn, bg_pixmap, vistype, resolution[0], resolution[1]);
     cairo_t *xcb_ctx = cairo_create(xcb_output);
 
@@ -272,7 +284,7 @@ xcb_pixmap_t draw_image(uint32_t *resolution) {
     timeinfo = localtime(&rawtime);
 
     if (unlock_indicator &&
-        (unlock_state >= STATE_KEY_PRESSED || auth_state > STATE_AUTH_IDLE || show_clock)) {
+        (unlock_state >= STATE_KEY_PRESSED || auth_state > STATE_AUTH_IDLE)) {
         cairo_scale(ctx, scaling_factor(), scaling_factor());
         /* Draw a (centered) circle with transparent background. */
         cairo_set_line_width(ctx, 7.0);
@@ -348,13 +360,8 @@ xcb_pixmap_t draw_image(uint32_t *resolution) {
 
         cairo_set_line_width(ctx, 10.0);
 
-        /* Display a (centered) text of the current PAM state. */
         char *text = NULL;
 
-        char *date = NULL;
-        char time_text[40] = {0};
-        char date_text[40] = {0};
-
         /* We don't want to show more than a 3-digit number. */
         char buf[4];
 
@@ -383,52 +390,10 @@ xcb_pixmap_t draw_image(uint32_t *resolution) {
                         text = buf;
                     }
                     cairo_set_font_size(ctx, 32.0);
-                } else if (show_clock) {
-                    strftime(time_text, 40, time_format, timeinfo);
-                    strftime(date_text, 40, date_format, timeinfo);
-                    text = time_text;
-                    date = date_text;
                 } 
                 break;
         }
 
-        if (text) {
-            cairo_text_extents_t extents;
-            double x, y;
-
-            cairo_select_font_face(ctx, time_font, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
-            cairo_set_source_rgba(ctx, (double)clock16[0]/255, (double)clock16[1]/255, (double)clock16[2]/255, (double)clock16[3]/255);
-            cairo_text_extents(ctx, text, &extents);
-            x = BUTTON_CENTER - ((extents.width / 2) + extents.x_bearing);
-            if (date) {
-                y = BUTTON_CENTER - ((extents.height / 2) + extents.y_bearing) - 6;
-            } else {
-                y = BUTTON_CENTER - ((extents.height / 2) + extents.y_bearing);
-            }
-
-            cairo_move_to(ctx, x, y);
-            cairo_show_text(ctx, text);
-            cairo_close_path(ctx);
-        }
-
-        if (date) {
-            cairo_text_extents_t extents;
-            double x, y;
-
-            cairo_select_font_face(ctx, date_font, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
-            cairo_set_source_rgba(ctx, (double)clock16[0]/255, (double)clock16[1]/255, (double)clock16[2]/255, (double)clock16[3]/255);
-            cairo_set_font_size(ctx, 14.0);
-
-            cairo_text_extents(ctx, date, &extents);
-            x = BUTTON_CENTER - ((extents.width / 2) + extents.x_bearing);
-            y = BUTTON_CENTER - ((extents.height / 2) + extents.y_bearing) + 14;
-
-            cairo_move_to(ctx, x, y);
-            cairo_show_text(ctx, date);
-            cairo_close_path(ctx);
-        }
-
-
         if (auth_state == STATE_AUTH_WRONG && (modifier_string != NULL)) {
             cairo_text_extents_t extents;
             double x, y;
@@ -487,39 +452,141 @@ xcb_pixmap_t draw_image(uint32_t *resolution) {
             cairo_stroke(ctx);
         }
     }
+    if (show_clock) {
+        char *text = NULL;
+        char *date = NULL;
+        char time_text[40] = {0};
+        char date_text[40] = {0};
+
+        strftime(time_text, 40, time_format, timeinfo);
+        strftime(date_text, 40, date_format, timeinfo);
+        text = time_text;
+        date = date_text;
+
+        double width = 0;
+        double height = 0;
+
+        if (text) {
+            double x, y;
+            cairo_text_extents_t extents;
+            cairo_set_font_size(clock_ctx, 32.0);
+            cairo_select_font_face(clock_ctx, time_font, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+            cairo_set_source_rgba(clock_ctx, (double)clock16[0]/255, (double)clock16[1]/255, (double)clock16[2]/255, (double)clock16[3]/255);
+            cairo_text_extents(clock_ctx, text, &extents);
+            x = CLOCK_WIDTH/2 - ((extents.width / 2) + extents.x_bearing);
+            y = CLOCK_HEIGHT/2 - extents.height;
+
+            cairo_move_to(clock_ctx, x, y);
+            cairo_show_text(clock_ctx, text);
+            cairo_close_path(clock_ctx);
+        }
+
+        if (date) {
+            double x, y;
+            cairo_text_extents_t extents;
+
+            cairo_select_font_face(clock_ctx, date_font, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+            cairo_set_source_rgba(clock_ctx, (double)clock16[0]/255, (double)clock16[1]/255, (double)clock16[2]/255, (double)clock16[3]/255);
+            cairo_set_font_size(clock_ctx, 14.0);
+
+            cairo_text_extents(clock_ctx, date, &extents);
+            x = CLOCK_WIDTH/2 - ((extents.width / 2) + extents.x_bearing);
+            y = CLOCK_HEIGHT/2;
+
+            cairo_move_to(clock_ctx, x, y);
+            cairo_show_text(clock_ctx, date);
+            cairo_close_path(clock_ctx);
+        }
+    }
+
+    double ix, iy;
+    double x, y;
+    double w, h;
+
+    int te_x_err;
+    int te_y_err;
+    // variable mapping for evaluating the clock position expression
+    te_variable vars[] = {{"ix", &ix}, {"iy", &iy}, {"w", &w}, {"h", &h}}; 
+
+    te_expr *x_expr = te_compile(clock_x_expr, vars, 4, &te_x_err);
+    te_expr *y_expr = te_compile(clock_y_expr, vars, 4, &te_y_err);
+
+
 
     if (xr_screens > 0) {
         /* Composite the unlock indicator in the middle of each screen. */
         // excuse me, just gonna hack something in right here
         if (screen_number != -1 && screen_number < xr_screens) {
-          int x = (xr_resolutions[screen_number].x + ((xr_resolutions[screen_number].width / 2) - (button_diameter_physical / 2)));
+          w = xr_resolutions[screen_number].width;
-          int y = (xr_resolutions[screen_number].y + ((xr_resolutions[screen_number].height / 2) - (button_diameter_physical / 2)));
+          h = xr_resolutions[screen_number].height;
+          ix = xr_resolutions[screen_number].x + (xr_resolutions[screen_number].width / 2);
+          iy = xr_resolutions[screen_number].y + (xr_resolutions[screen_number].height / 2);
+          x = ix - (button_diameter_physical / 2);
+          y = iy - (button_diameter_physical / 2);
           cairo_set_source_surface(xcb_ctx, output, x, y);
           cairo_rectangle(xcb_ctx, x, y, button_diameter_physical, button_diameter_physical);
-          cairo_fill(xcb_ctx);        }
+          cairo_fill(xcb_ctx);        
+
+          if (x_expr && y_expr) {
+              double clock_x = xr_resolutions[screen_number].x + te_eval(x_expr) - CLOCK_WIDTH / 2;
+              double clock_y = xr_resolutions[screen_number].y + te_eval(y_expr) - CLOCK_HEIGHT / 2;
+              cairo_set_source_surface(xcb_ctx, clock_output, clock_x, clock_y);
+              cairo_rectangle(xcb_ctx, clock_x, clock_y, CLOCK_WIDTH, CLOCK_HEIGHT);
+              cairo_fill(xcb_ctx);
+          }
+        }
         else {
           for (int screen = 0; screen < xr_screens; screen++) {
-              int x = (xr_resolutions[screen].x + ((xr_resolutions[screen].width / 2) - (button_diameter_physical / 2)));
+              w = xr_resolutions[screen].width;
-              int y = (xr_resolutions[screen].y + ((xr_resolutions[screen].height / 2) - (button_diameter_physical / 2)));
+              h = xr_resolutions[screen].height;
+              ix = xr_resolutions[screen].x + (xr_resolutions[screen].width / 2);
+              iy = xr_resolutions[screen].y + (xr_resolutions[screen].height / 2);
+              x = ix - (button_diameter_physical / 2);
+              y = iy - (button_diameter_physical / 2);
               cairo_set_source_surface(xcb_ctx, output, x, y);
               cairo_rectangle(xcb_ctx, x, y, button_diameter_physical, button_diameter_physical);
               cairo_fill(xcb_ctx);
+              if (x_expr && y_expr) {
+                  double clock_x = xr_resolutions[screen].x + te_eval(x_expr) - CLOCK_WIDTH / 2;
+                  double clock_y = xr_resolutions[screen].y + te_eval(y_expr) - CLOCK_HEIGHT / 2;
+                  cairo_set_source_surface(xcb_ctx, clock_output, clock_x, clock_y);
+                  cairo_rectangle(xcb_ctx, clock_x, clock_y, CLOCK_WIDTH, CLOCK_HEIGHT);
+                  cairo_fill(xcb_ctx);
+              }
+          else {
+              DEBUG("error codes for exprs are %d, %d\n", te_x_err, te_y_err);
+              DEBUG("exprs: %s, %s\n", clock_x_expr, clock_y_expr);
+          }
           }
         }
     } else {
         /* We have no information about the screen sizes/positions, so we just
          * place the unlock indicator in the middle of the X root window and
          * hope for the best. */
-        int x = (last_resolution[0] / 2) - (button_diameter_physical / 2);
+        w = last_resolution[0];
-        int y = (last_resolution[1] / 2) - (button_diameter_physical / 2);
+        h = last_resolution[1];
+        ix = last_resolution[0] / 2;
+        iy = last_resolution[1] / 2;
+        x = ix - (button_diameter_physical / 2);
+        y = iy - (button_diameter_physical / 2);
         cairo_set_source_surface(xcb_ctx, output, x, y);
         cairo_rectangle(xcb_ctx, x, y, button_diameter_physical, button_diameter_physical);
         cairo_fill(xcb_ctx);
+        if (x_expr && y_expr) {
+            double clock_x = te_eval(x_expr) - CLOCK_WIDTH / 2;
+            double clock_y = te_eval(y_expr) - CLOCK_HEIGHT / 2;
+            DEBUG("Placing clock at %f, %f\n", clock_x, clock_y);
+            cairo_set_source_surface(xcb_ctx, clock_output, clock_x, clock_y);
+            cairo_rectangle(xcb_ctx, clock_x, clock_y, CLOCK_WIDTH, CLOCK_HEIGHT);
+            cairo_fill(xcb_ctx);
+        }
     }
 
     cairo_surface_destroy(xcb_output);
+    cairo_surface_destroy(clock_output);
     cairo_surface_destroy(output);
     cairo_destroy(ctx);
+    cairo_destroy(clock_ctx);
     cairo_destroy(xcb_ctx);
     return bg_pixmap;
 }