From f2dd61123f38c620062518a995c865854bb1ac1c Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Fri, 23 Jul 2021 23:04:31 +0200
Subject: Added primitive image loading

---
 markdown.cpp | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/markdown.cpp b/markdown.cpp
index e8b4e71..6c94a97 100644
--- a/markdown.cpp
+++ b/markdown.cpp
@@ -11,6 +11,7 @@
 #include <string>
 #include <string_view>
 #include <thread>
+#include <unordered_map>
 
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
@@ -20,11 +21,23 @@
 #include <imgui_impl_opengl3.h>
 #include <imgui_md.h>
 
+#define STB_IMAGE_IMPLEMENTATION
+#include <stb_image.h>
+
 std::string g_base_address;
 ImFont * g_font_regular;
 ImFont * g_font_bold;
 ImFont * g_font_bold_large;
 
+struct Image
+{
+	ImTextureID m_texture_id;
+	int m_width;
+	int m_height;
+};
+
+std::unordered_map<std::string, Image> g_images;
+
 static std::string get(const std::string & command)
 {
 	std::string result;
@@ -65,6 +78,31 @@ static std::string expand_url(const std::string & href)
 	}
 }
 
+static bool load_image(const std::string & filename, Image & image)
+{
+	unsigned char * data = stbi_load(filename.c_str(), &image.m_width, &image.m_height, nullptr, 4);
+	if (nullptr == data)
+		return false;
+	GLuint texture;
+	glGenTextures(1, &texture);
+	glBindTexture(GL_TEXTURE_2D, texture);
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+#if defined(GL_UNPACK_ROW_LENGTH)
+	glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+#endif
+
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.m_width, image.m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
+	stbi_image_free(data);
+	image.m_texture_id = reinterpret_cast<ImTextureID>(texture);
+
+	return true;
+}
+
 struct Markdown : public imgui_md
 {
 	ImFont * get_font() const override
@@ -91,6 +129,32 @@ struct Markdown : public imgui_md
 		std::thread t(std::move(task), command);
 		t.detach();
 	}
+
+	bool get_image(image_info & nfo) const override
+	{
+		auto search = g_images.find(m_href);
+		if (g_images.end() == search)
+		{
+			std::string command = "phttp " + expand_url(m_href);
+			std::packaged_task<std::string (const std::string &)> task(get);
+			auto future = task.get_future();
+			std::thread t(std::move(task), command);
+			t.detach();
+			const auto result = future.get();
+			auto n = result.find(" ");
+			n = result.find(" ", n + 1);
+			const auto filename = result.substr(n + 1, result.size() - n - 2);
+			if (!load_image(filename, g_images[m_href]))
+				throw std::runtime_error("could not load image");
+		}
+		nfo.texture_id = g_images[m_href].m_texture_id;
+		nfo.size = {g_images[m_href].m_width, g_images[m_href].m_height};
+		nfo.uv0 = {0, 0};
+		nfo.uv1 = {1, 1};
+		nfo.col_tint = {1, 1, 1, 1};
+		nfo.col_border = {0, 0, 0, 0};
+		return true;
+	}
 };
 
 static void glfw_error_callback(int error, const char * description)
-- 
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