4.SVG

svg.cpp

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+#include "svg.h"
+#include <iostream>
+#include <vector>
+
+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, string text) {
+    cout << "<text x='" << left << "' y='" << baseline << "'>" << text << "</text>";
+}
+
+void svg_rect(double x, double y, double width, double height, string stroke = "black", string fill = "black"){
+    cout << "<rect x='" << x << "' y='" << y << "' width='" << width << "' height='" << height << "' stroke='" << stroke << "' fill='#" << fill << "' />";
+}
+
+void
+show_histogram_svg(const vector<double>& bins) {
+
+    const auto IMAGE_WIDTH = 400;
+    const auto IMAGE_HEIGHT = 300;
+    const auto TEXT_LEFT = 20;
+    const auto TEXT_BASELINE = 20;
+    const auto TEXT_WIDTH = 50;
+    const auto BIN_HEIGHT = 30;
+    const auto BLOCK_WIDTH = 10;
+
+    svg_begin(400, 300);
+
+    double top = 0;
+    const size_t MAX_ASTERISK = IMAGE_WIDTH - TEXT_WIDTH;
+    double maxb = bins[0];
+
+    for (size_t j = 1; j < bins.size(); j++)
+    {
+        if (bins[j] > maxb) maxb = bins[j];
+    }
+
+    maxb = maxb * BLOCK_WIDTH;
+
+    for (size_t bin : bins) {
+
+    double bin_width;
+
+        if (maxb > MAX_ASTERISK)
+        {
+            bin_width  = BLOCK_WIDTH * MAX_ASTERISK * (bin / maxb);
+        }
+        else bin_width = BLOCK_WIDTH * bin;
+
+    svg_text(TEXT_LEFT, top + TEXT_BASELINE, to_string(bin));
+    svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT, "red", "ffeeee");
+    top += BIN_HEIGHT;
+}
+
+    svg_end();
+}

svg.h

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+#pragma once
+#include <vector>
+
+void
+show_histogram_svg(const std::vector<double>& bins);