4. SVG

main.cpp

@@ -31,5 +31,5 @@ int
 main() {
     auto in = input_data();
     auto bins = make_histogram(in.numbers, in.bin_count);
-    show_histogram_text(bins);
+    show_histogram_svg(bins);
 }

svg.cpp

@@ -0,0 +1,66 @@
+#include "svg.h"
+
+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, string fill){
+    cout << "<rect x='" << x << "' y='" << y <<"' width='" << width << "' height='" << height << "' stroke='" << stroke << "' fill='" << fill << "'/>";
+}
+void
+show_histogram_svg(const vector<size_t>& 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;
+
+    size_t maxbin = 0;
+    for (size_t bin : bins){
+        if (bin > maxbin){
+            maxbin = bin;
+        }
+    }
+    if (maxbin * BLOCK_WIDTH <= IMAGE_WIDTH - TEXT_WIDTH){
+        for (size_t bin : bins) {
+            const double bin_width = BLOCK_WIDTH * bin;
+            svg_text(TEXT_LEFT, top + TEXT_BASELINE, to_string(bin));
+            svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT);
+            top += BIN_HEIGHT;
+        }
+        svg_end();
+    }
+    else{
+        float kf = static_cast<double>(IMAGE_WIDTH - TEXT_WIDTH) / (maxbin * BLOCK_WIDTH);
+        for (size_t bin : bins) {
+            const double bin_width = BLOCK_WIDTH * bin * kf;
+            svg_text(TEXT_LEFT, top + TEXT_BASELINE, to_string(bin));
+            svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT);
+            top += BIN_HEIGHT;
+        }
+        svg_end();
+    }
+}

svg.h

@@ -0,0 +1,15 @@
+#pragma once
+#include <iostream>
+#include <vector>
+#include<string>
+
+void
+svg_begin(double width, double height);
+void
+svg_end();
+void
+svg_text(double left, double baseline, std::string text);
+void
+svg_rect(double x, double y, double width, double height, std::string stroke = "black", std::string fill = "black");
+void
+show_histogram_svg(const std::vector<size_t>& bins);