I need sample code to insert an Image into a page. about go-pdfium HOT 13 CLOSED

type matrix struct {
	a float32
	b float32
	c float32
	d float32
	e float32
	f float32
}

func newMatrix(a, b, c, d, e, f float32) *matrix {
	m := matrix{
		a: a,
		b: b,
		c: c,
		d: d,
		e: e,
		f: f,
	}
	if m.a == 0 {
		m.a = 1
	}
	if m.d == 0 {
		m.d = 1
	}

	return &m
}

func newDefaultMatrix() *matrix {
	return newMatrix(0, 0, 0, 0, 0, 0)
}

func (m *matrix) multiply(other *matrix) *matrix {
	return newMatrix(
		m.a*other.a+m.b*other.c,
		m.a*other.b+m.b*other.d,
		m.c*other.a+m.d*other.c,
		m.c*other.b+m.d*other.d,
		m.e*other.a+m.f*other.c+other.e,
		m.e*other.b+m.f*other.d+other.f,
	)
}

func (m *matrix) scale(x, y float32) *matrix {
	return m.multiply(newMatrix(x, 0, 0, y, 0, 0))
}

func newImageToPage(ctx context.Context, doc references.FPDF_DOCUMENT, imageBuffer []byte) error {
	instance := GetInstance(ctx)
	img, err := instance.FPDFPageObj_NewImageObj(&requests.FPDFPageObj_NewImageObj{
		Document: doc,
	})
	if err != nil {
		return err
	}
	imgObject := img.PageObject
	defer closePageObject(ctx, imgObject)
	_, err = instance.FPDFImageObj_LoadJpegFile(&requests.FPDFImageObj_LoadJpegFile{
		ImageObject:    imgObject,
		FileReader:     bytes.NewReader(imageBuffer),
		FileReaderSize: int64(len(imageBuffer)),
	})
	if err != nil {
		return err
	}
	size, err := instance.FPDFImageObj_GetImagePixelSize(&requests.FPDFImageObj_GetImagePixelSize{
		ImageObject: imgObject,
	})
	if err != nil {
		return err
	}
	m := newDefaultMatrix().scale(float32(size.Width), float32(size.Height))
	_, err = instance.FPDFImageObj_SetMatrix(&requests.FPDFImageObj_SetMatrix{
		ImageObject: imgObject,
		Transform: structs.FPDF_FS_MATRIX{
			A: m.a,
			B: m.b,
			C: m.c,
			D: m.d,
			E: m.e,
			F: m.f,
		},
	})
	if err != nil {
		return err
	}
	page, err := instance.FPDFPage_New(&requests.FPDFPage_New{
		Document: doc,
		Width:    float64(size.Width),
		Height:   float64(size.Height),
	})
	if err != nil {
		return err
	}
	defer ClosePage(ctx, page.Page)
	_, err = instance.FPDFPage_InsertObject(&requests.FPDFPage_InsertObject{
		Page: requests.Page{
			ByReference: &page.Page,
		},
		PageObject: imgObject,
	})
	if err != nil {
		return err
	}
	_, err = instance.FPDFPage_GenerateContent(&requests.FPDFPage_GenerateContent{
		Page: requests.Page{
			ByReference: &page.Page,
		},
	})
	if err != nil {
		return err
	}
	if err != nil {
		return err
	}
	return nil
}