Usage docs

README.md

@@ -1,5 +1,5 @@
 # go-libheif
- GoLang wrapper for the libheif library, providing easy-to-use APIs for HEIC to JPEG/PNG conversions and vice versa.
+ GoLang wrapper for the libheif library, providing easy-to-use APIs for HEIC to JPEG/PNG conversions and vice versa. (Also provides support for AVIF to JPEG/PNG conversions)
 
 ### Pre-requisites
 You need to install [libheif](https://github.com/strukturag/libheif) before using this module. You can check the [strukturag/libheif](https://github.com/strukturag/libheif) for installation instructions, but as I have found, the easiest way for me was to use [brew](https://brew.sh/):
@@ -15,11 +15,80 @@ go get github.com/MaestroError/go-libheif
 ```
 
 ### Usage
-...
+This library provides functions to convert images between HEIC format and other common formats such as JPEG and PNG.       
+
+To convert an image from HEIC / HEIF / AVIF to JPEG or PNG:
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/MaestroError/go-libheif"
+)
+
+func main() {
+	err := go_libheif.HeifToJpeg("input.heic", "output.jpeg", 80)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = go_libheif.HeifToPng("input.heic", "output.png")
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+```
+
+To convert an image from JPEG or PNG to HEIC:
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/MaestroError/go-libheif"
+)
+
+func main() {
+	err := go_libheif.ImageToHeif("input.jpeg", "output.heic")
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+```
+*Note: It finds hard to convert some jpeg and png files to heic, see libheif_test.go:14 for details*       
+
+To save an image as HEIC:
+```go
+package main
+
+import (
+	"image"
+	"log"
+
+	"github.com/MaestroError/go-libheif"
+)
+
+func main() {
+	img := image.NewRGBA(image.Rect(0, 0, 100, 100))
+	err := go_libheif.SaveImageAsHeif(img, "png", "output.heic")
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+```
+*Note: Quality for **HeifToJpeg** function and image format for **SaveImageAsHeif** function should be provided. The quality value ranges from 1 to 100 inclusive, higher values meaning better quality. The format for **SaveImageAsHeif** is the format of the original image.*       
+
+Please consult the GoDoc documentation for more detailed information about the provided functions and their usage.          
+
 
 ##### ToDo
-- Refactor the functions to return errors instead +
-- Add documentation and examples for each function +
-- Write tests at least for the Public functions +
-- Write usage documentation
-- Write guide article for module
+- Write usage documentation +
+- Write guide article for module
+- Add contribution section in readme
+- Implement the module in [php-heic-to-jpg](https://github.com/MaestroError/php-heic-to-jpg)
+- Add credits section in readme and update in php-heic-to-jpg