ps graph

CMakeLists.txt

@@ -14,6 +14,7 @@ add_executable(Graph
     "lex.c"
     "parser.c"
     "tree.c"
+    "ps_graph.c"
 )
 
 # Optionally, you can set compiler warnings

main.c

@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include "lex.h"
 #include "parser.h"
+#include "ps_graph.h"
 
 int main(int argc, char *argv[]) { 
 
@@ -22,14 +23,35 @@ int main(int argc, char *argv[]) {
     node = parse_expression(lex);
     lex_free(lex);
 
+    //if (node) {
+    //    double x;
+    //    node_debug_print(node);
+    //    printf("polygon(");
+    //    for (x = -10.0; x < 10.0; x += 0.1) {
+    //        printf("(%.2f,%.2f),", x, node_eval(node, x));
+    //    }
+    //    printf("(10, -1000),(-10,-1000))\n");
+    //}
+
     if (node) {
-        double x;
-        node_debug_print(node);
-        printf("polygon(");
-        for (x = -10.0; x < 10.0; x += 0.1) {
-            printf("(%.2f,%.2f),", x, node_eval(node, x));
-        }
-        printf("(10, -1000),(-10,-1000))\n");
+        FILE *file;
+        struct graph_range graph;
+        //graph.xmin = -10.0;
+        //graph.xmax = 10.0;
+        //graph.ymin = -10.0;
+        //graph.ymax = 10.0;
+        //graph.step = 0.1;
+
+        graph.xmin = -3.14;
+        graph.xmax = 3.14;
+        graph.ymin = -1;
+        graph.ymax = 1;
+        graph.step = 0.01;
+
+
+        file = fopen("out.ps", "w");
+        ps_export_graph(file, node, &graph);
+        fclose(file);
     }
 
     node_free(node);

ps_graph.c

@@ -0,0 +1,114 @@
+#include "ps_graph.h"
+
+#define GRAPH_SIZE 400
+#define HALF_GRAPH_SIZE (GRAPH_SIZE / 2)
+#define GRID_STEP (GRAPH_SIZE / 10)
+
+void ps_export_graph(FILE *file, struct expr_node *node, struct graph_range *range) {
+    int i;
+    double x;
+    int first = 1;
+
+    fprintf(file,
+        "306 500 translate\n"
+        "2 setlinewidth\n"
+        "/gridline {\n"
+        "   .5 setlinewidth\n"
+        "   .5 setgray\n"
+        "   [3 3] 0 setdash\n"
+        "   newpath\n"
+        "   moveto\n"
+        "   rlineto\n"
+        "   stroke\n"
+        "} def\n"
+        "\n"
+    );
+
+    /* mrizka */
+    for (i = -HALF_GRAPH_SIZE + GRID_STEP; i < HALF_GRAPH_SIZE; i += GRID_STEP) {
+        fprintf(file, "%5d     0 %5d %5d gridline\n", GRAPH_SIZE, -HALF_GRAPH_SIZE, i);
+        fprintf(file, "    0 %5d %5d %5d gridline\n", GRAPH_SIZE, i, -HALF_GRAPH_SIZE);
+    }
+
+    /* popisky */
+    fprintf(file,
+        "/Arial findfont\n"
+        "12 scalefont\n"
+        "setfont\n"
+    );
+
+    for (i = -HALF_GRAPH_SIZE; i <= HALF_GRAPH_SIZE; i += GRID_STEP) {
+        double inorm = (double)i / (double)GRAPH_SIZE + 0.5;
+        double xval = range->xmax * inorm + range->xmin * (1.0 - inorm) ; // range->xmin + inorm * (range->xmax - range->xmin);
+        double yval = range->ymax * inorm + range->ymin * (1.0 - inorm) ; // range->xmin + inorm * (range->xmax - range->xmin);
+        
+        fprintf(file,
+            "newpath\n"
+            "%d %d moveto\n"
+            "(%.2f) dup\n"
+            "stringwidth pop neg\n"
+            "0 rmoveto\n"
+            "-10 -3 rmoveto\n"
+            "show\n"
+            "\n",
+            -HALF_GRAPH_SIZE, i, yval
+        );
+
+        fprintf(file,
+            "newpath\n"
+            "%d %d moveto\n"
+            "(%.2f) dup\n"
+            "stringwidth pop\n"
+            "2 div neg\n"
+            "-20 rmoveto\n"
+            "show\n"
+            "\n",
+            i, -HALF_GRAPH_SIZE, xval
+        );
+
+    }
+
+    fprintf(file,
+        "[] 0 setdash\n"
+        "newpath\n"
+        "%d %d moveto\n"
+        "%d 0 rlineto\n"
+        "0 %d rlineto\n"
+        "%d 0 rlineto\n"
+        "closepath\n"
+        "gsave\n"
+        "clip\n",
+        -HALF_GRAPH_SIZE, -HALF_GRAPH_SIZE, GRAPH_SIZE, GRAPH_SIZE, -GRAPH_SIZE 
+    );
+
+    fprintf(file,
+        "2 setlinewidth\n"
+        "0 .3 .7 setrgbcolor\n"
+        "newpath\n"
+    );
+
+    for (x = range->xmin; x <= range->xmax; x += range->step) {
+        double y = node_eval(node, x);
+        double xpos = (double)(-HALF_GRAPH_SIZE) + (x - range->xmin) / (range->xmax - range->xmin) * (double)GRAPH_SIZE;
+        double ypos = (double)(-HALF_GRAPH_SIZE) + (y - range->ymin) / (range->ymax - range->ymin) * (double)GRAPH_SIZE;
+        const char* cmd = "lineto";
+        if (first) {
+            cmd = "moveto";
+            first = 0;
+        }
+        fprintf(file, "%.2f %.2f %s\n", xpos, ypos, cmd);
+    }
+
+    fprintf(file,
+        "stroke\n"
+    );
+
+    fprintf(file,
+        "grestore\n"
+        "2 setlinewidth\n"
+        "0 0 0 setrgbcolor\n"
+        "stroke\n"
+    );
+
+
+}

ps_graph.h

@@ -0,0 +1,15 @@
+#ifndef PS_GRAPH_H
+#define PS_GRAPH_H
+
+#include <stdio.h>
+#include "tree.h"
+
+struct graph_range {
+	double xmin, xmax;
+	double ymin, ymax;
+	double step;
+};
+
+extern void ps_export_graph(FILE *file, struct expr_node *node, struct graph_range *range);
+
+#endif