improve graphics package

.gitignore

@@ -30,3 +30,4 @@ inv.jpg
 2
 .DS_Store
 /.idea
+*_example.png

graphics/example_test.go

@@ -1,32 +1,141 @@
 package graphics_test
 
 import (
+	"fmt"
+	"image"
+	"image/png"
+	"os"
+
 	"simonwaldherr.de/go/golibs/graphics"
 	//"../graphics"
 )
 
-func Example() {
-	img := graphics.LoadImage("img.jpg")
-	img_gray := graphics.Grayscale(img)
+func ExampleRNN() {
+	img := createTestImage()
 
 	img_rnn, _ := graphics.NearestNeighbor(img, 80, 24)
+	saveImage("rnn_example.png", img_rnn)
+	fmt.Println("Inverted image saved to rnn_example.png")
+	// Output: Inverted image saved to rnn_example.png
+}
+
+func ExampleInvert() {
+	img := createTestImage()
+
+	invertedImg, _ := graphics.Invert(img)
+	saveImage("invert_example.png", invertedImg)
+	fmt.Println("Inverted image saved to invert_example.png")
+	// Output: Inverted image saved to invert_example.png
+}
+
+func ExampleGrayscale() {
+	img := createTestImage()
+
+	grayImg := graphics.Grayscale(img)
+	saveImage("grayscale_example.png", grayImg)
+	fmt.Println("Grayscale image saved to grayscale_example.png")
+	// Output: Grayscale image saved to grayscale_example.png
+}
+
+func ExampleGaussianBlur() {
+	img := createTestImage()
+
+	blurredImg := graphics.GaussianBlur(img)
+	saveImage("gaussian_blur_example.png", blurredImg)
+	fmt.Println("Gaussian blurred image saved to gaussian_blur_example.png")
+	// Output: Gaussian blurred image saved to gaussian_blur_example.png
+}
+
+func ExampleSharpen() {
+	img := createTestImage()
+
+	sharpenedImg := graphics.Sharpen(img)
+	saveImage("sharpen_example.png", sharpenedImg)
+	fmt.Println("Sharpened image saved to sharpen_example.png")
+	// Output: Sharpened image saved to sharpen_example.png
+}
+
+func ExampleEdgeDetect() {
+	img := createTestImage()
+
+	edgeImg := graphics.EdgeDetect(img)
+	saveImage("edge_detect_example.png", edgeImg)
+	fmt.Println("Edge detected image saved to edge_detect_example.png")
+	// Output: Edge detected image saved to edge_detect_example.png
+}
 
-	img_each, _ := graphics.EachPixelOfImage(img, func(r, g, b, a uint8) (uint8, uint8, uint8, uint8) {
-		return g, b, r, a
-	})
+func ExampleThreshold() {
+	img := createTestImage()
 
-	img_edge := graphics.Edgedetect(img)
+	threshImg := graphics.Threshold(img, 128)
+	saveImage("threshold_example.png", threshImg)
+	fmt.Println("Thresholded image saved to threshold_example.png")
+	// Output: Thresholded image saved to threshold_example.png
+}
+
+func ExampleAdjustBrightness() {
+	img := createTestImage()
+
+	brightImg := graphics.AdjustBrightness(img, 30)
+	saveImage("brightness_example.png", brightImg)
+	fmt.Println("Brightness adjusted image saved to brightness_example.png")
+	// Output: Brightness adjusted image saved to brightness_example.png
+}
+
+func ExampleAdjustContrast() {
+	img := createTestImage()
 
-	img_invert, _ := graphics.Invert(img)
+	contrastImg := graphics.AdjustContrast(img, 1.5)
+	saveImage("contrast_example.png", contrastImg)
+	fmt.Println("Contrast adjusted image saved to contrast_example.png")
+	// Output: Contrast adjusted image saved to contrast_example.png
+}
+
+func ExampleSepia() {
+	img := createTestImage()
+
+	sepiaImg := graphics.Sepia(img)
+	saveImage("sepia_example.png", sepiaImg)
+	fmt.Println("Sepia image saved to sepia_example.png")
+	// Output: Sepia image saved to sepia_example.png
+}
 
-	img_threshold := graphics.Threshold(img, 128)
+func ExampleRotate90() {
+	img := createTestImage()
+
+	rotatedImg := graphics.Rotate90(img)
+	saveImage("rotate90_example.png", rotatedImg)
+	fmt.Println("Rotated image saved to rotate90_example.png")
+	// Output: Rotated image saved to rotate90_example.png
+}
+
+func ExampleFlipHorizontal() {
+	img := createTestImage()
+
+	flippedImg := graphics.FlipHorizontal(img)
+	saveImage("flip_horizontal_example.png", flippedImg)
+	fmt.Println("Flipped image saved to flip_horizontal_example.png")
+	// Output: Flipped image saved to flip_horizontal_example.png
+}
+
+// createTestImage creates a simple test image
+func createTestImage() image.Image {
+	img, _ := graphics.LoadImage("img.jpg")
+
+	return img
+}
 
-	graphics.SaveImage(img_gray, "img_gray.png")
-	graphics.SaveImage(img_rnn, "img_rnn.png")
-	graphics.SaveImage(img_each, "img_each.png")
-	graphics.SaveImage(img_edge, "img_edge.png")
-	graphics.SaveImage(img_invert, "img_invert.png")
-	graphics.SaveImage(img_threshold, "img_threshold.png")
+// saveImage saves an image to a file
+func saveImage(filename string, img image.Image) {
+	f, err := os.Create(filename)
+	if err != nil {
+		fmt.Println("Failed to create file:", err)
+		return
+	}
+	defer f.Close()
 
-	// Output:
+	err = png.Encode(f, img)
+	if err != nil {
+		fmt.Println("Failed to encode image:", err)
+	}
 }