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 TestGenerateMMFlashWithText(t *testing.T) {
+	tc := testutil.SystemTest(t)
+
+	t.Setenv("GOOGLE_GENAI_USE_VERTEXAI", "1")
+	t.Setenv("GOOGLE_CLOUD_LOCATION", "us-central1")
+	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-preview"
+	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-preview"
+	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]