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Improve doc. comments & rename 'fill' arg. to 'optFill'
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@balacode
balacode committed Apr 4, 2018
1 parent c10374a commit fe497c6
Showing 1 changed file with 41 additions and 34 deletions.
75 changes: 41 additions & 34 deletions one_file_pdf.go
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@@ -1,8 +1,9 @@
// -----------------------------------------------------------------------------
// (c) balarabe@protonmail.com License: MIT
// :v: 2018-04-03 00:06:12 66EB99 [one_file_pdf.go]
// :v: 2018-04-04 01:26:51 7C71B9 [one_file_pdf.go]
// -----------------------------------------------------------------------------

// Package pdf provides a PDF writer type to generate PDF files.
package pdf

// # Main Structure and Constructor
Expand Down Expand Up @@ -45,9 +46,10 @@ package pdf
// # Methods (ob *PDF)
// AddPage() *PDF
// Bytes() []byte
// DrawBox(x, y, width, height float64, fill ...bool) *PDF
// DrawCircle(x, y, radius float64, fill ...bool) *PDF
// DrawEllipse(x, y, xRadius, yRadius float64, fill ...bool) *PDF
// DrawBox(x, y, width, height float64, optFill ...bool) *PDF
// DrawCircle(x, y, radius float64, optFill ...bool) *PDF
// DrawEllipse(x, y, xRadius, yRadius float64,
// optFill ...bool) *PDF
// DrawImage(x, y, height float64, fileNameOrBytes interface{},
// backColor ...string) *PDF
// DrawLine(x1, y1, x2, y2 float64) *PDF
Expand Down Expand Up @@ -109,7 +111,7 @@ package pdf
// write(format string, args ...interface{}) *PDF
// writeCurve(x1, y1, x2, y2, x3, y3 float64) *PDF
// writeEndobj() *PDF
// writeMode(fill ...bool) (mode string)
// writeMode(optFill ...bool) (mode string)
// writeObj(objType string) *PDF
// writePages(pagesIndex, fontsIndex, imagesIndex int) *PDF
// writeStream(content []byte) *PDF
Expand Down Expand Up @@ -224,19 +226,19 @@ func (ob *PDF) Color() color.RGBA { ob.init(); return ob.color }
// which is useful for debugging or to study PDF commands.
func (ob *PDF) Compression() bool { ob.init(); return ob.compression }

// DocAuthor returns the optional 'document author' metadata entry.
// DocAuthor returns the optional 'document author' metadata property.
func (ob *PDF) DocAuthor() string { ob.init(); return ob.docAuthor }

// DocCreator returns the optional 'document creator' metadata entry.
// DocCreator returns the optional 'document creator' metadata property.
func (ob *PDF) DocCreator() string { ob.init(); return ob.docCreator }

// DocKeywords returns the optional 'document keywords' metadata entry.
// DocKeywords returns the optional 'document keywords' metadata property.
func (ob *PDF) DocKeywords() string { ob.init(); return ob.docKeywords }

// DocSubject returns the optional 'document subject' metadata entry.
// DocSubject returns the optional 'document subject' metadata property.
func (ob *PDF) DocSubject() string { ob.init(); return ob.docSubject }

// DocTitle returns the optional 'document subject' metadata entry.
// DocTitle returns the optional 'document subject' metadata property.
func (ob *PDF) DocTitle() string { ob.init(); return ob.docTitle }

// FontName returns the name of the currently-active typeface.
Expand Down Expand Up @@ -298,19 +300,19 @@ func (ob *PDF) SetCompression(val bool) *PDF {
return ob
} // SetCompression

// SetDocAuthor sets the optional 'document author' metadata entry.
// SetDocAuthor sets the optional 'document author' metadata property.
func (ob *PDF) SetDocAuthor(s string) *PDF { ob.docAuthor = s; return ob }

// SetDocCreator sets the optional 'document creator' metadata entry.
// SetDocCreator sets the optional 'document creator' metadata property.
func (ob *PDF) SetDocCreator(s string) *PDF { ob.docCreator = s; return ob }

// SetDocKeywords sets the optional 'document keywords' metadata entry.
// SetDocKeywords sets the optional 'document keywords' metadata property.
func (ob *PDF) SetDocKeywords(s string) *PDF { ob.docKeywords = s; return ob }

// SetDocSubject sets the optional 'document subject' metadata entry.
// SetDocSubject sets the optional 'document subject' metadata property.
func (ob *PDF) SetDocSubject(s string) *PDF { ob.docSubject = s; return ob }

// SetDocTitle sets the optional 'document title' metadata entry.
// SetDocTitle sets the optional 'document title' metadata property.
func (ob *PDF) SetDocTitle(s string) *PDF { ob.docTitle = s; return ob }

// SetFont changes the current font name and size in points.
Expand Down Expand Up @@ -472,31 +474,36 @@ func (ob *PDF) Bytes() []byte {
return ob.content.Bytes()
} // Bytes

// DrawBox draws a rectangle.
func (ob *PDF) DrawBox(x, y, width, height float64, fill ...bool) *PDF {
// DrawBox draws a rectangle of the specified width and height,
// with the top-left corner starting at point (x, y).
// To fill the rectangle, pass true in the optional optFill.
func (ob *PDF) DrawBox(x, y, width, height float64, optFill ...bool) *PDF {
width, height = width*ob.ptPerUnit, height*ob.ptPerUnit
x, y = x*ob.ptPerUnit, ob.paperSize.heightPt-y*ob.ptPerUnit-height
var mode = ob.writeMode(fill...)
var mode = ob.writeMode(optFill...)
return ob.write("%.3f %.3f %.3f %.3f re %s\n", x, y, width, height, mode)
// re: construct a rectangular path
} // DrawBox

// DrawCircle draws a circle of radius r centered on (x, y),
// by drawing 4 Bézier curves (PDF has no circle primitive)
func (ob *PDF) DrawCircle(x, y, radius float64, fill ...bool) *PDF {
return ob.DrawEllipse(x, y, radius, radius, fill...)
// To fill the circle, pass true in the optional optFill.
func (ob *PDF) DrawCircle(x, y, radius float64, optFill ...bool) *PDF {
return ob.DrawEllipse(x, y, radius, radius, optFill...)
} // DrawCircle

// DrawEllipse draws an ellipse centered on (x, y),
// with horizontal radius xRadius and vertical radius yRadius
// by drawing 4 Bézier curves (PDF has no ellipse primitive)
func (ob *PDF) DrawEllipse(x, y, xRadius, yRadius float64, fill ...bool) *PDF {
// by drawing 4 Bézier curves (PDF has no ellipse primitive).
// To fill the ellipse, pass true in the optional optFill.
func (ob *PDF) DrawEllipse(x, y, xRadius, yRadius float64,
optFill ...bool) *PDF {
x, y = x*ob.ptPerUnit, ob.paperSize.heightPt-y*ob.ptPerUnit
const ratio = 0.552284749830794 // (4/3) * tan(PI/8)
var r = xRadius * ob.ptPerUnit // horizontal radius
var v = yRadius * ob.ptPerUnit // vertical radius
var m, n = r * ratio, v * ratio // ratios for control points
var mode = ob.writeMode(fill...) // prepare colors/line width
const ratio = 0.552284749830794 // (4/3) * tan(PI/8)
var r = xRadius * ob.ptPerUnit // horizontal radius
var v = yRadius * ob.ptPerUnit // vertical radius
var m, n = r * ratio, v * ratio // ratios for control points
var mode = ob.writeMode(optFill...) // prepare colors/line width
//
return ob.write(" %.3f %.3f m", x-r, y). // x0 y0 m: move to point (x0, y0)
// control-1 control-2 endpoint
Expand Down Expand Up @@ -750,7 +757,7 @@ func (ob *PDF) ToUnits(points float64) float64 {

// WrapTextLines splits a string into multiple lines so that the text
// fits in the specified width. The text is wrapped on word boundaries.
// Newline characters (CR and "\n") also cause text to be split.
// Newline characters ("\r" and "\n") also cause text to be split.
// You can find out the number of lines needed to wrap some
// text by checking the length of the returned array.
func (ob *PDF) WrapTextLines(width float64, text string) (ret []string) {
Expand Down Expand Up @@ -1105,7 +1112,7 @@ func (ob *PDF) loadImage(fileNameOrBytes interface{}, back color.RGBA,
func makeImage(source image.Image, back color.RGBA,
) (widthPx, heightPx int, isGray bool, ar []byte) {
//
// blends color into the background 'back', using opacity (alpha) value
// blends color into the background (back), using opacity (alpha) value
var blend = func(color, alpha uint32, back byte) byte {
var c, a = float64(color), 65535 - float64(alpha) // range 0-65535
return byte((c + (float64(back)*255-c)/65536*a) / 65536 * 255)
Expand Down Expand Up @@ -1199,10 +1206,10 @@ func (ob *PDF) writeEndobj() *PDF {

// writeMode sets the stroking or non-stroking color and line width.
// 'fill' arg specifies non-stroking (true) or stroking mode (none/false)
func (ob *PDF) writeMode(fill ...bool) (mode string) {
func (ob *PDF) writeMode(optFill ...bool) (mode string) {
ob.reservePage()
mode = "S" // S: stroke path (for lines)
if len(fill) > 0 && fill[0] {
if len(optFill) > 0 && optFill[0] {
mode = "b" // b: fill / text
if pv := &ob.ppage.nonStrokeColor; *pv != ob.color {
*pv = ob.color
Expand Down Expand Up @@ -1279,7 +1286,7 @@ func (ob *PDF) writeStream(content []byte) *PDF {

// writeStreamData writes a stream or image stream
func (ob *PDF) writeStreamData(ar []byte) *PDF {
var s string // filter
var flt string // filter
if ob.compression {
var buf bytes.Buffer
var wr = zlib.NewWriter(&buf)
Expand All @@ -1289,9 +1296,9 @@ func (ob *PDF) writeStreamData(ar []byte) *PDF {
}
wr.Close() // don't defer, close before reading Bytes()
ar = buf.Bytes()
s = "/Filter/FlateDecode"
flt = "/Filter/FlateDecode"
}
return ob.write("%s/Length %d>>stream\n%s\nendstream\n", s, len(ar), ar)
return ob.write("%s/Length %d>>stream\n%s\nendstream\n", flt, len(ar), ar)
} // writeStreamData

// -----------------------------------------------------------------------------
Expand Down

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