fix wrong git ignore

internal/pdf/creator/image.go

@@ -0,0 +1,329 @@
+package creator
+
+import (
+	"bytes"
+	"fmt"
+	goimage "image"
+	"os"
+
+	"gitea.tecamino.com/paadi/pdfmerge/internal/pdf/common"
+	"gitea.tecamino.com/paadi/pdfmerge/internal/pdf/contentstream"
+	"gitea.tecamino.com/paadi/pdfmerge/internal/pdf/core"
+	"gitea.tecamino.com/paadi/pdfmerge/internal/pdf/model"
+)
+
+// The Image type is used to draw an image onto PDF.
+type Image struct {
+	xobj *model.XObjectImage
+	img  *model.Image
+
+	// Rotation angle.
+	angle float64
+
+	// The dimensions of the image. As to be placed on the PDF.
+	width, height float64
+
+	// The original dimensions of the image (pixel based).
+	origWidth, origHeight float64
+
+	// Positioning: relative / absolute.
+	positioning positioning
+
+	// Absolute coordinates (when in absolute mode).
+	xPos float64
+	yPos float64
+
+	// Opacity (alpha value).
+	opacity float64
+
+	// Margins to be applied around the block when drawing on Page.
+	margins margins
+
+	// Encoder
+	encoder core.StreamEncoder
+}
+
+// NewImage create a new image from a image (model.Image).
+func NewImage(img *model.Image) (*Image, error) {
+	image := &Image{}
+	image.img = img
+
+	// Image original size in points = pixel size.
+	image.origWidth = float64(img.Width)
+	image.origHeight = float64(img.Height)
+	image.width = image.origWidth
+	image.height = image.origHeight
+	image.angle = 0
+	image.opacity = 1.0
+
+	image.positioning = positionRelative
+
+	return image, nil
+}
+
+// NewImageFromData creates an Image from image data.
+func NewImageFromData(data []byte) (*Image, error) {
+	imgReader := bytes.NewReader(data)
+
+	// Load the image with default handler.
+	img, err := model.ImageHandling.Read(imgReader)
+	if err != nil {
+		common.Log.Error("error loading image: %s", err)
+		return nil, err
+	}
+
+	return NewImage(img)
+}
+
+// NewImageFromFile creates an Image from a file.
+func NewImageFromFile(path string) (*Image, error) {
+	imgData, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	img, err := NewImageFromData(imgData)
+	if err != nil {
+		return nil, err
+	}
+
+	return img, nil
+}
+
+// NewImageFromGoImage creates an Image from a go image.Image datastructure.
+func NewImageFromGoImage(goimg goimage.Image) (*Image, error) {
+	img, err := model.ImageHandling.NewImageFromGoImage(goimg)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewImage(img)
+}
+
+// SetEncoder sets the encoding/compression mechanism for the image.
+func (img *Image) SetEncoder(encoder core.StreamEncoder) {
+	img.encoder = encoder
+}
+
+// Height returns Image's document height.
+func (img *Image) Height() float64 {
+	return img.height
+}
+
+// Width returns Image's document width.
+func (img *Image) Width() float64 {
+	return img.width
+}
+
+// SetOpacity sets opacity for Image.
+func (img *Image) SetOpacity(opacity float64) {
+	img.opacity = opacity
+}
+
+// SetMargins sets the margins for the Image (in relative mode): left, right, top, bottom.
+func (img *Image) SetMargins(left, right, top, bottom float64) {
+	img.margins.left = left
+	img.margins.right = right
+	img.margins.top = top
+	img.margins.bottom = bottom
+}
+
+// GetMargins returns the Image's margins: left, right, top, bottom.
+func (img *Image) GetMargins() (float64, float64, float64, float64) {
+	return img.margins.left, img.margins.right, img.margins.top, img.margins.bottom
+}
+
+// makeXObject makes the encoded XObject Image that will be used in the PDF.
+func (img *Image) makeXObject() error {
+	encoder := img.encoder
+	if encoder == nil {
+		// Default: Use flate encoder.
+		encoder = core.NewFlateEncoder()
+	}
+
+	// Create the XObject image.
+	ximg, err := model.NewXObjectImageFromImage(img.img, nil, encoder)
+	if err != nil {
+		common.Log.Error("Failed to create xobject image: %s", err)
+		return err
+	}
+
+	img.xobj = ximg
+	return nil
+}
+
+// GeneratePageBlocks generate the Page blocks. Draws the Image on a block, implementing the Drawable interface.
+func (img *Image) GeneratePageBlocks(ctx DrawContext) ([]*Block, DrawContext, error) {
+	if img.xobj == nil {
+		// Build the XObject Image if not already prepared.
+		img.makeXObject()
+	}
+
+	blocks := []*Block{}
+	origCtx := ctx
+
+	blk := NewBlock(ctx.PageWidth, ctx.PageHeight)
+	if img.positioning.isRelative() {
+		if img.height > ctx.Height {
+			// Goes out of the bounds.  Write on a new template instead and create a new context at upper
+			// left corner.
+
+			blocks = append(blocks, blk)
+			blk = NewBlock(ctx.PageWidth, ctx.PageHeight)
+
+			// New Page.
+			ctx.Page++
+			newContext := ctx
+			newContext.Y = ctx.Margins.top // + p.Margins.top
+			newContext.X = ctx.Margins.left + img.margins.left
+			newContext.Height = ctx.PageHeight - ctx.Margins.top - ctx.Margins.bottom - img.margins.bottom
+			newContext.Width = ctx.PageWidth - ctx.Margins.left - ctx.Margins.right - img.margins.left - img.margins.right
+			ctx = newContext
+		} else {
+			ctx.Y += img.margins.top
+			ctx.Height -= img.margins.top + img.margins.bottom
+			ctx.X += img.margins.left
+			ctx.Width -= img.margins.left + img.margins.right
+		}
+	} else {
+		// Absolute.
+		ctx.X = img.xPos
+		ctx.Y = img.yPos
+	}
+
+	// Place the Image on the template at position (x,y) based on the ctx.
+	ctx, err := drawImageOnBlock(blk, img, ctx)
+	if err != nil {
+		return nil, ctx, err
+	}
+
+	blocks = append(blocks, blk)
+
+	if img.positioning.isAbsolute() {
+		// Absolute drawing should not affect context.
+		ctx = origCtx
+	} else {
+		// XXX/TODO: Use projected height.
+		ctx.Y += img.margins.bottom
+		ctx.Height -= img.margins.bottom
+	}
+
+	return blocks, ctx, nil
+}
+
+// SetPos sets the absolute position. Changes object positioning to absolute.
+func (img *Image) SetPos(x, y float64) {
+	img.positioning = positionAbsolute
+	img.xPos = x
+	img.yPos = y
+}
+
+// Scale scales Image by a constant factor, both width and height.
+func (img *Image) Scale(xFactor, yFactor float64) {
+	img.width = xFactor * img.width
+	img.height = yFactor * img.height
+}
+
+// ScaleToWidth scale Image to a specified width w, maintaining the aspect ratio.
+func (img *Image) ScaleToWidth(w float64) {
+	ratio := img.height / img.width
+	img.width = w
+	img.height = w * ratio
+}
+
+// ScaleToHeight scale Image to a specified height h, maintaining the aspect ratio.
+func (img *Image) ScaleToHeight(h float64) {
+	ratio := img.width / img.height
+	img.height = h
+	img.width = h * ratio
+}
+
+// SetWidth set the Image's document width to specified w. This does not change the raw image data, i.e.
+// no actual scaling of data is performed. That is handled by the PDF viewer.
+func (img *Image) SetWidth(w float64) {
+	img.width = w
+}
+
+// SetHeight sets the Image's document height to specified h.
+func (img *Image) SetHeight(h float64) {
+	img.height = h
+}
+
+// SetAngle sets Image rotation angle in degrees.
+func (img *Image) SetAngle(angle float64) {
+	img.angle = angle
+}
+
+// Draw the image onto the specified blk.
+func drawImageOnBlock(blk *Block, img *Image, ctx DrawContext) (DrawContext, error) {
+	origCtx := ctx
+
+	// Find a free name for the image.
+	num := 1
+	imgName := core.PdfObjectName(fmt.Sprintf("Img%d", num))
+	for blk.resources.HasXObjectByName(imgName) {
+		num++
+		imgName = core.PdfObjectName(fmt.Sprintf("Img%d", num))
+	}
+
+	// Add to the Page resources.
+	err := blk.resources.SetXObjectImageByName(imgName, img.xobj)
+	if err != nil {
+		return ctx, err
+	}
+
+	// Find an available GS name.
+	i := 0
+	gsName := core.PdfObjectName(fmt.Sprintf("GS%d", i))
+	for blk.resources.HasExtGState(gsName) {
+		i++
+		gsName = core.PdfObjectName(fmt.Sprintf("GS%d", i))
+	}
+
+	// Graphics state with normal blend mode.
+	gs0 := core.MakeDict()
+	gs0.Set("BM", core.MakeName("Normal"))
+	if img.opacity < 1.0 {
+		gs0.Set("CA", core.MakeFloat(img.opacity))
+		gs0.Set("ca", core.MakeFloat(img.opacity))
+	}
+
+	err = blk.resources.AddExtGState(gsName, core.MakeIndirectObject(gs0))
+	if err != nil {
+		return ctx, err
+	}
+
+	xPos := ctx.X
+	yPos := ctx.PageHeight - ctx.Y - img.Height()
+	angle := img.angle
+
+	// Create content stream to add to the Page contents.
+	contentCreator := contentstream.NewContentCreator()
+
+	contentCreator.Add_gs(gsName) // Set graphics state.
+
+	contentCreator.Translate(xPos, yPos)
+	if angle != 0 {
+		// Make the rotation about the upper left corner.
+		contentCreator.Translate(0, img.Height())
+		contentCreator.RotateDeg(angle)
+		contentCreator.Translate(0, -img.Height())
+	}
+
+	contentCreator.
+		Scale(img.Width(), img.Height()).
+		Add_Do(imgName) // Draw the image.
+
+	ops := contentCreator.Operations()
+	ops.WrapIfNeeded()
+
+	blk.addContents(ops)
+
+	if img.positioning.isRelative() {
+		ctx.Y += img.Height()
+		ctx.Height -= img.Height()
+		return ctx, nil
+	}
+	// Absolute positioning - return original context.
+	return origCtx, nil
+}