svg: Вывод гистограммы как изображения в формате SVG

svg.cpp

@@ -0,0 +1,69 @@
+#include "svg.h"
+#include <string>
+using namespace std;
+
+void svg_begin(double width, double height) {
+    cout << "<?xml version='1.0' encoding='UTF-8'?>\n";
+    cout << "<svg ";
+    cout << "width='" << width << "' ";
+    cout << "height='" << height << "' ";
+    cout << "viewBox='0 0 " << width << " " << height << "' ";
+    cout << "xmlns='http://www.w3.org/2000/svg'>\n";
+}
+
+void svg_end() {
+    cout << "</svg>\n";
+}
+void svg_text(double left, double baseline, const string& text) {
+    cout << "<text x='" << left
+        << "' y='" << baseline
+        << "'>" << text
+        << "</text>\n";
+}
+
+void svg_rect(double x, double y, double width, double height,
+    const string& stroke, const string& fill) {
+    cout << "<rect x='" << x
+        << "' y='" << y
+        << "' width='" << width
+        << "' height='" << height
+        << "' stroke='" << stroke
+        << "' fill='" << fill
+        << "' />\n";
+}
+void show_histogram_svg(const vector<size_t>& bins) {
+    const double IMAGE_WIDTH = 400;
+    const double IMAGE_HEIGHT = 300;
+    const double TEXT_LEFT = 20;
+    const double TEXT_BASELINE = 20;
+    const double TEXT_WIDTH = 50;
+    const double BIN_HEIGHT = 30;
+    const double BLOCK_WIDTH = 10;
+
+    svg_begin(IMAGE_WIDTH, IMAGE_HEIGHT);
+
+    size_t max_count = 0;
+    for (size_t count : bins) {
+        if (count > max_count) {
+            max_count = count;
+        }
+    }
+
+    double max_width = IMAGE_WIDTH - TEXT_WIDTH;
+    double top = 0;
+    for (size_t count : bins) {
+        double bin_width;
+        if (max_count > 0) {
+            bin_width = static_cast<double>(count) / max_count * max_width;
+        }
+        else {
+            bin_width = 0.0;
+        }
+
+        svg_text(TEXT_LEFT, top + TEXT_BASELINE, to_string(count));
+        svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT, "blue", "blue");
+        top += BIN_HEIGHT;
+    }
+
+    svg_end();
+}