base ppt export

lib/ppt/pptx.go

@@ -0,0 +1,111 @@
+package ppt
+
+import (
+	"archive/zip"
+	"bytes"
+	_ "embed"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// Office Open XML (OOXML) http://officeopenxml.com/prPresentation.php
+
+//go:embed template.pptx
+var pptx_template []byte
+
+func copyPptxTemplateTo(w *zip.Writer) error {
+	reader := bytes.NewReader(pptx_template)
+	zipReader, err := zip.NewReader(reader, reader.Size())
+	if err != nil {
+		fmt.Printf("%v", err)
+	}
+
+	for _, f := range zipReader.File {
+		fw, err := w.Create(f.Name)
+		if err != nil {
+			return err
+		}
+		fr, err := f.Open()
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(fw, fr)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func addFile(zipFile *zip.Writer, filePath, content string) error {
+	w, err := zipFile.Create(filePath)
+	if err != nil {
+		return err
+	}
+	w.Write([]byte(content))
+	return nil
+}
+
+// https://startbigthinksmall.wordpress.com/2010/01/04/points-inches-and-emus-measuring-units-in-office-open-xml/
+const SLIDE_WIDTH = 9144000
+const SLIDE_HEIGHT = 5143500
+
+const RELS_SLIDE_XML = `<?xml version='1.0' encoding='UTF-8' standalone='yes'?><Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"><Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideLayout" Target="../slideLayouts/slideLayout7.xml" /><Relationship Id="%s" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="../media/%s.png" /></Relationships>`
+
+func getRelsSlideXml(imageId string) string {
+	return fmt.Sprintf(RELS_SLIDE_XML, imageId, imageId)
+}
+
+const SLIDE_XML = `<?xml version='1.0' encoding='UTF-8' standalone='yes'?><p:sld xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main" xmlns:p="http://schemas.openxmlformats.org/presentationml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><p:cSld><p:spTree><p:nvGrpSpPr><p:cNvPr id="1" name="" /><p:cNvGrpSpPr /><p:nvPr /></p:nvGrpSpPr><p:grpSpPr /><p:pic><p:nvPicPr><p:cNvPr id="2" name="%s" descr="%s" /><p:cNvPicPr><a:picLocks noChangeAspect="1" /></p:cNvPicPr><p:nvPr /></p:nvPicPr><p:blipFill><a:blip r:embed="%s" /><a:stretch><a:fillRect /></a:stretch></p:blipFill><p:spPr><a:xfrm><a:off x="%d" y="%d" /><a:ext cx="%d" cy="%d" /></a:xfrm><a:prstGeom prst="rect"><a:avLst /></a:prstGeom></p:spPr></p:pic></p:spTree></p:cSld><p:clrMapOvr><a:masterClrMapping /></p:clrMapOvr></p:sld>`
+
+func getSlideXml(imageId, imageName string, top, left, width, height int) string {
+	return fmt.Sprintf(SLIDE_XML, imageName, imageName, imageId, left, top, width, height)
+}
+
+func getPresentationXmlRels(slideFileNames []string) string {
+	var builder strings.Builder
+	builder.WriteString(`<?xml version='1.0' encoding='UTF-8' standalone='yes'?><Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"><Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/presProps" Target="presProps.xml" /><Relationship Id="rId4" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/viewProps" Target="viewProps.xml" /><Relationship Id="rId5" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/theme" Target="theme/theme1.xml" /><Relationship Id="rId6" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/tableStyles" Target="tableStyles.xml" /><Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideMaster" Target="slideMasters/slideMaster1.xml" /><Relationship Id="rId2" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/printerSettings" Target="printerSettings/printerSettings1.bin" />`)
+
+	for _, name := range slideFileNames {
+		builder.WriteString(fmt.Sprintf(
+			`<Relationship Id="%s" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/slide" Target="slides/%s.xml" />`, name, name,
+		))
+	}
+
+	builder.WriteString("</Relationships>")
+
+	return builder.String()
+}
+
+func getContentTypesXml(slideFileNames []string) string {
+	var builder strings.Builder
+	builder.WriteString(`<?xml version='1.0' encoding='UTF-8' standalone='yes'?><Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types"><Default Extension="bin" ContentType="application/vnd.openxmlformats-officedocument.presentationml.printerSettings" /><Default Extension="jpeg" ContentType="image/jpeg" /><Default Extension="png" ContentType="image/png" /><Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml" /><Default Extension="xml" ContentType="application/xml" /><Override PartName="/docProps/app.xml" ContentType="application/vnd.openxmlformats-officedocument.extended-properties+xml" /><Override PartName="/docProps/core.xml" ContentType="application/vnd.openxmlformats-package.core-properties+xml" /><Override PartName="/ppt/presProps.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.presProps+xml" /><Override PartName="/ppt/presentation.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.presentation.main+xml" /><Override PartName="/ppt/slideLayouts/slideLayout1.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout10.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout11.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout2.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout3.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout4.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout5.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout6.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout7.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout8.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideLayouts/slideLayout9.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideLayout+xml" /><Override PartName="/ppt/slideMasters/slideMaster1.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slideMaster+xml" />`)
+
+	for _, name := range slideFileNames {
+		builder.WriteString(fmt.Sprintf(
+			`<Override PartName="/ppt/slides/%s.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.slide+xml" />`, name,
+		))
+	}
+
+	builder.WriteString(`<Override PartName="/ppt/tableStyles.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.tableStyles+xml" /><Override PartName="/ppt/theme/theme1.xml" ContentType="application/vnd.openxmlformats-officedocument.theme+xml" /><Override PartName="/ppt/viewProps.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.viewProps+xml" /></Types>`)
+	return builder.String()
+}
+
+func getPresentationXml(slideFileNames []string) string {
+	var builder strings.Builder
+	builder.WriteString(`<?xml version='1.0' encoding='UTF-8' standalone='yes'?><p:presentation xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:p="http://schemas.openxmlformats.org/presentationml/2006/main" saveSubsetFonts="1" autoCompressPictures="0"><p:sldMasterIdLst><p:sldMasterId id="2147483648" r:id="rId1" /></p:sldMasterIdLst>`)
+
+	builder.WriteString("<p:sldIdLst>")
+	for i, name := range slideFileNames {
+		builder.WriteString(fmt.Sprintf(`<p:sldId id="%d" r:id="%s" />`, i, name))
+	}
+	builder.WriteString("</p:sldIdLst>")
+
+	builder.WriteString(fmt.Sprintf(
+		`<p:sldSz cx="%d" cy="%d" type="screen4x3" /><p:notesSz cx="6858000" cy="9144000" /><p:defaultTextStyle><a:defPPr><a:defRPr lang="en-US" /></a:defPPr><a:lvl1pPr marL="0" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl1pPr><a:lvl2pPr marL="457200" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl2pPr><a:lvl3pPr marL="914400" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl3pPr><a:lvl4pPr marL="1371600" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl4pPr><a:lvl5pPr marL="1828800" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl5pPr><a:lvl6pPr marL="2286000" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl6pPr><a:lvl7pPr marL="2743200" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl7pPr><a:lvl8pPr marL="3200400" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl8pPr><a:lvl9pPr marL="3657600" algn="l" defTabSz="457200" rtl="0" eaLnBrk="1" latinLnBrk="0" hangingPunct="1"><a:defRPr sz="1800" kern="1200"><a:solidFill><a:schemeClr val="tx1" /></a:solidFill><a:latin typeface="+mn-lt" /><a:ea typeface="+mn-ea" /><a:cs typeface="+mn-cs" /></a:defRPr></a:lvl9pPr></p:defaultTextStyle></p:presentation>`,
+		SLIDE_WIDTH,
+		SLIDE_HEIGHT,
+	))
+	return builder.String()
+}

lib/ppt/presentation.go

@@ -0,0 +1,100 @@
+package ppt
+
+import (
+	"archive/zip"
+	"bytes"
+	_ "embed"
+	"fmt"
+	"image/png"
+	"os"
+)
+
+type Pptx struct {
+	Slides []*Slide
+}
+
+type Slide struct {
+	Image  []byte
+	Width  int
+	Height int
+}
+
+func NewPresentation() *Pptx {
+	return &Pptx{}
+}
+
+func (p *Pptx) AddSlide(pngContent []byte) error {
+	src, err := png.Decode(bytes.NewReader(pngContent))
+	if err != nil {
+		return fmt.Errorf("error decoding PNG image: %v", err)
+	}
+
+	srcSize := src.Bounds().Size()
+	height := int(float64(SLIDE_WIDTH) * (float64(srcSize.X) / float64(srcSize.Y)))
+
+	p.Slides = append(p.Slides, &Slide{
+		Image:  pngContent,
+		Width:  SLIDE_WIDTH,
+		Height: height,
+	})
+
+	return nil
+}
+
+func (p *Pptx) SaveTo(filePath string) error {
+	// TODO: update core files with metadata
+
+	f, err := os.Create(filePath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	zipFile := zip.NewWriter(f)
+	defer zipFile.Close()
+
+	copyPptxTemplateTo(zipFile)
+
+	var slideFileNames []string
+	for i, slide := range p.Slides {
+		imageId := fmt.Sprintf("slide%dImage", i+1)
+		slideFileName := fmt.Sprintf("slide%d", i+1)
+		slideFileNames = append(slideFileNames, slideFileName)
+
+		imageWriter, err := zipFile.Create(fmt.Sprintf("ppt/media/%s.png", imageId))
+		if err != nil {
+			return err
+		}
+		_, err = imageWriter.Write(slide.Image)
+		if err != nil {
+			return err
+		}
+
+		err = addFile(zipFile, fmt.Sprintf("ppt/slides/_rels/%s.xml.rels", slideFileName), getRelsSlideXml(imageId))
+		if err != nil {
+			return err
+		}
+
+		// TODO: center the image?
+		err = addFile(zipFile, fmt.Sprintf("ppt/slides/%s.xml", slideFileName), getSlideXml(imageId, imageId, 0, 0, slide.Width, slide.Height))
+		if err != nil {
+			return err
+		}
+	}
+
+	err = addFile(zipFile, "[Content_Types].xml", getContentTypesXml(slideFileNames))
+	if err != nil {
+		return err
+	}
+
+	err = addFile(zipFile, "ppt/_rels/presentation.xml.rels", getPresentationXmlRels(slideFileNames))
+	if err != nil {
+		return err
+	}
+
+	err = addFile(zipFile, "ppt/presentation.xml", getPresentationXml(slideFileNames))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}