feat(genai): Add samples for image generation

genai/image_generation/image_generation_examples_test.go

@@ -0,0 +1,58 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image_generation
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/GoogleCloudPlatform/golang-samples/internal/testutil"
+)
+
+func TestImageGeneration(t *testing.T) {
+	tc := testutil.SystemTest(t)
+
+	t.Setenv("GOOGLE_GENAI_USE_VERTEXAI", "1")
+	t.Setenv("GOOGLE_CLOUD_LOCATION", "global")
+	t.Setenv("GOOGLE_CLOUD_PROJECT", tc.ProjectID)
+
+	buf := new(bytes.Buffer)
+
+	t.Run("generate multimodal flash content with text and image", func(t *testing.T) {
+		buf.Reset()
+		err := generateMMFlashWithText(buf)
+		if err != nil {
+			t.Fatalf("generateMMFlashWithText failed: %v", err)
+		}
+
+		output := buf.String()
+		if output == "" {
+			t.Error("expected non-empty output, got empty")
+		}
+	})
+
+	t.Run("generate mmflash text and image recipe", func(t *testing.T) {
+		buf.Reset()
+		err := generateMMFlashTxtImgWithText(buf)
+		if err != nil {
+			t.Fatalf("generateMMFlashTxtImgWithText failed: %v", err)
+		}
+
+		output := buf.String()
+		if output == "" {
+			t.Error("expected non-empty output, got empty")
+		}
+	})
+}

genai/image_generation/imggen_mmflash_txt_img_with_txt.go

@@ -0,0 +1,105 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package image_generation shows how to use the GenAI SDK to generate images and text.
+package image_generation
+
+// [START googlegenaisdk_imggen_mmflash_txt_and_img_with_txt]
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"google.golang.org/genai"
+)
+
+// generateMMFlashTxtImgWithText demonstrates how to generate an illustrated recipe
+// combining text and image outputs into a markdown file.
+func generateMMFlashTxtImgWithText(w io.Writer) error {
+	ctx := context.Background()
+
+	client, err := genai.NewClient(ctx, &genai.ClientConfig{
+		HTTPOptions: genai.HTTPOptions{APIVersion: "v1"},
+	})
+	if err != nil {
+		return fmt.Errorf("failed to create genai client: %w", err)
+	}
+
+	modelName := "gemini-2.5-flash-image"
+	contents := []*genai.Content{
+		{
+			Parts: []*genai.Part{
+				{Text: "Generate an illustrated recipe for a paella. " +
+					"Create images to go alongside the text as you generate the recipe."},
+			},
+			Role: "user",
+		},
+	}
+
+	resp, err := client.Models.GenerateContent(ctx,
+		modelName,
+		contents,
+		&genai.GenerateContentConfig{
+			ResponseModalities: []string{
+				string(genai.ModalityText),
+				string(genai.ModalityImage),
+			},
+			CandidateCount: int32(1),
+		},
+	)
+	if err != nil {
+		return fmt.Errorf("failed to generate content: %w", err)
+	}
+
+	if len(resp.Candidates) == 0 || resp.Candidates[0].Content == nil {
+		return fmt.Errorf("no candidates returned")
+	}
+
+	outputFolder := "testdata"
+
+	// Create the markdown file
+	mdFile := filepath.Join(outputFolder, "paella-recipe.md")
+	fp, err := os.Create(mdFile)
+	if err != nil {
+		return fmt.Errorf("failed to create markdown file: %w", err)
+	}
+	defer fp.Close()
+
+	for i, part := range resp.Candidates[0].Content.Parts {
+		if part.Text != "" {
+			if _, err := fp.WriteString(part.Text); err != nil {
+				return fmt.Errorf("failed to write text: %w", err)
+			}
+		} else if part.InlineData != nil {
+			imgFile := filepath.Join(outputFolder, fmt.Sprintf("example-image-%d.png", i+1))
+			if err := os.WriteFile(imgFile, part.InlineData.Data, 0644); err != nil {
+				return fmt.Errorf("failed to save image: %w", err)
+			}
+			if _, err := fp.WriteString(fmt.Sprintf("![image](%s)", filepath.Base(imgFile))); err != nil {
+				return fmt.Errorf("failed to write image reference: %w", err)
+			}
+		}
+	}
+
+	fmt.Fprintln(w, mdFile)
+
+	// Example response:
+	//  A markdown page for a Paella recipe (`paella-recipe.md`) has been generated.
+	//  It includes detailed steps and several images illustrating the cooking process.
+	return nil
+}
+
+// [END googlegenaisdk_imggen_mmflash_txt_and_img_with_txt]

genai/image_generation/imggen_mmflash_with_txt.go

@@ -0,0 +1,92 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package image_generation shows how to use the GenAI SDK to generate images and text.
+package image_generation
+
+// [START googlegenaisdk_imggen_mmflash_with_txt]
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+
+	"google.golang.org/genai"
+)
+
+// generateMMFlashWithText demonstrates how to generate both text and image outputs.
+func generateMMFlashWithText(w io.Writer) error {
+	ctx := context.Background()
+
+	client, err := genai.NewClient(ctx, &genai.ClientConfig{
+		HTTPOptions: genai.HTTPOptions{APIVersion: "v1"},
+	})
+	if err != nil {
+		return fmt.Errorf("failed to create genai client: %w", err)
+	}
+
+	modelName := "gemini-2.5-flash-image"
+	contents := []*genai.Content{
+		{
+			Parts: []*genai.Part{
+				{Text: "Generate an image of the Eiffel tower with fireworks in the background."},
+			},
+			Role: "user",
+		},
+	}
+
+	resp, err := client.Models.GenerateContent(ctx,
+		modelName,
+		contents,
+		&genai.GenerateContentConfig{
+			ResponseModalities: []string{
+				string(genai.ModalityText),
+				string(genai.ModalityImage),
+			},
+			CandidateCount: int32(1),
+			SafetySettings: []*genai.SafetySetting{
+				{Method: genai.HarmBlockMethodProbability},
+				{Category: genai.HarmCategoryDangerousContent},
+				{Threshold: genai.HarmBlockThresholdBlockMediumAndAbove},
+			},
+		},
+	)
+	if err != nil {
+		return fmt.Errorf("failed to generate content: %w", err)
+	}
+
+	if len(resp.Candidates) == 0 || resp.Candidates[0].Content == nil {
+		return fmt.Errorf("no candidates returned")
+	}
+	var fileName string
+	for _, part := range resp.Candidates[0].Content.Parts {
+		if part.Text != "" {
+			fmt.Fprintln(w, part.Text)
+		} else if part.InlineData != nil {
+			fileName = "testdata/example-image-eiffel-tower.png"
+			if err := os.WriteFile(fileName, part.InlineData.Data, 0o644); err != nil {
+				return fmt.Errorf("failed to save image: %w", err)
+			}
+		}
+	}
+	fmt.Fprintln(w, fileName)
+
+	// Example response:
+	// I will generate an image of the Eiffel Tower at night, with a vibrant display of
+	// colorful fireworks exploding in the dark sky behind it.
+	// ....
+	return nil
+}
+
+// [END googlegenaisdk_imggen_mmflash_with_txt]

genai/image_generation/testdata/paella-recipe.md

@@ -0,0 +1,44 @@
+Let's get cooking! Here's an illustrated recipe for a delicious paella:
+
+## Traditional Spanish Paella
+
+Paella is a classic Spanish dish, known for its vibrant colors and rich flavors. While there are many variations, this recipe will guide you through making a traditional chicken and seafood paella.
+
+### Ingredients:
+
+*   2 tablespoons olive oil
+*   1 lb boneless, skinless chicken thighs, cut into 1-inch pieces
+*   1 lb shrimp, peeled and deveined
+*   1 cup chopped chorizo (optional)
+*   1 large onion, chopped
+*   2 cloves garlic, minced
+*   1 red bell pepper, chopped
+*   1 (14.5 ounce) can diced tomatoes, undrained
+*   1 teaspoon smoked paprika
+*   1/2 teaspoon saffron threads, crushed and steeped in 1/4 cup warm water
+*   2 cups Bomba rice (or other short-grain rice)
+*   4 cups chicken broth, warmed
+*   1/2 cup frozen peas
+*   1/4 cup chopped fresh parsley
+*   Lemon wedges, for serving
+*   Salt and freshly ground black pepper to taste
+
+### Equipment:
+
+*   Large paella pan (or a large, shallow, oven-safe pan)
+*   Wooden spoon
+
+### Instructions:
+
+**Step 1: Prepare Your Ingredients**
+
+Before you start cooking, it's helpful to have all your ingredients prepped and ready to go. Chop your chicken, onion, bell pepper, and mince your garlic. Don't forget to steep your saffron threads!
+![image](example-image-2.png)**Step 2: Sauté the Chicken and Chorizo**
+
+Heat the olive oil in your paella pan over medium-high heat. Add the chicken pieces and cook until browned on all sides. If using, add the chorizo and cook until lightly crisped. Remove the chicken and chorizo from the pan and set aside, leaving any drippings in the pan.
+
+![image](example-image-4.png)**Step 3: Cook the Aromatics**
+
+Add the chopped onion and bell pepper to the pan and cook until softened, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant.
+
+![image](example-image-6.png)