First commit

.gitattributes

@@ -0,0 +1 @@
+* text=auto eol=lf

.gitignore

@@ -0,0 +1,9 @@
+# Environment variables file
+.env
+
+# Distributable directory
+dist/
+
+# Test data and logs folders
+.data/
+.idea/dataSources.xml

.idea/.gitignore

@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/discord.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="DiscordProjectSettings">
+    <option name="show" value="PROJECT_FILES" />
+    <option name="description" value="" />
+  </component>
+</project>

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/png2ico.iml" filepath="$PROJECT_DIR$/.idea/png2ico.iml" />
+    </modules>
+  </component>
+</project>

.idea/png2ico.iml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="Go" enabled="true" />
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

README.md

@@ -0,0 +1,4 @@
+png2ico
+===========
+
+Convert PNG image to ICO image

go.mod

@@ -0,0 +1,3 @@
+module tea.melonie54.xyz/sean/png2ico
+
+go 1.17

png2ico.go

@@ -0,0 +1,53 @@
+package png2ico
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+type iconDir struct {
+	reserved  uint16
+	imageType uint16
+	numImages uint16
+}
+
+type iconDirEntry struct {
+	imageWidth   uint8
+	imageHeight  uint8
+	numColors    uint8
+	reserved     uint8
+	colorPlanes  uint16
+	bitsPerPixel uint16
+	sizeInBytes  uint32
+	offset       uint32
+}
+
+func newIconDir() iconDir {
+	return iconDir{imageType: 1, numImages: 1}
+}
+
+func newIconDirEntry() iconDirEntry {
+	return iconDirEntry{colorPlanes: 1, bitsPerPixel: 32, offset: 22}
+}
+
+func ConvertPngToIco(im []byte, width, height int) ([]byte, error) {
+	id := newIconDir()
+	ide := newIconDirEntry()
+
+	ide.sizeInBytes = uint32(len(im))
+	ide.imageWidth = uint8(width)
+	ide.imageHeight = uint8(height)
+	bb := new(bytes.Buffer)
+
+	err := binary.Write(bb, binary.LittleEndian, id)
+	if err != nil {
+		return nil, err
+	}
+	err = binary.Write(bb, binary.LittleEndian, ide)
+	if err != nil {
+		return nil, err
+	}
+
+	bb.Write(im)
+	return bb.Bytes(), nil
+}