From 12b19fab33a097c8ff7335eee4ef0f9bf7047790 Mon Sep 17 00:00:00 2001
From: Michael Ochmann <michael.ochmann@propeller.de>
Date: Wed, 22 Feb 2023 17:04:13 +0100
Subject: [PATCH] fixed illegal memory accesses

---
 src/PNGRenderer.hpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/PNGRenderer.hpp b/src/PNGRenderer.hpp
index 8fa5587..065e508 100644
--- a/src/PNGRenderer.hpp
+++ b/src/PNGRenderer.hpp
@@ -5,6 +5,7 @@
 #include <vector>
 #include <string>
 #include <iostream>
+#include <math.h>
 
 #include "stb_image_write.hpp"
 #include "Renderer.hpp"
@@ -21,7 +22,7 @@ class PNGRenderer : public Renderer {
 		std::vector<Color> bitmap;
 
 		void drawPixelScaled(size_t x, size_t y, Color color) {
-			size_t pixelSize = this->targetSize / (this->sourceSize + 2);
+			size_t pixelSize = floor(static_cast<float>(this->targetSize) / static_cast<float>(this->sourceSize + 2));
 
 			if (pixelSize < 1) {
 				std::cerr << "ERROR: output file size is too small" << std::endl;
@@ -41,19 +42,20 @@ class PNGRenderer : public Renderer {
 	public:
 		PNGRenderer(const std::vector<bool>& pixels, size_t sourceSize, size_t targetSize) : Renderer(pixels, sourceSize, targetSize) {
 			if (this->targetSize == 0)
-				this->targetSize = sourceSize;
-			this->bitmap = std::vector<Color>(targetSize * targetSize, 0xFFFFFFFF);
+				this->targetSize = (sourceSize + 2) * 2;
+			this->bitmap = std::vector<Color>(this->targetSize * this->targetSize, PNGRenderer::WHITE);
 		}
 
 		virtual void render(const std::string& filename) override {
 			for (size_t y = 0; y < sourceSize; y++) {
 				for (size_t x = 0; x < sourceSize; x++) {
-					Color color = pixels.at(y * sourceSize + x) ? PNGRenderer::BLACK : PNGRenderer::WHITE;
-					this->drawPixelScaled(x, y, color);
+					if (!pixels.at(y * sourceSize + x))
+						continue;
+					this->drawPixelScaled(x, y, PNGRenderer::BLACK);
 				}
 			}
 
-			stbi_write_png(filename.c_str(), targetSize, targetSize, 4, this->bitmap.data(), targetSize * sizeof(Color));
+			stbi_write_png(filename.c_str(), targetSize, targetSize, 4, this->bitmap.data(), sizeof(Color) * targetSize);
 		}
 
 };