add/revise vips_text function

vips/create.c

@@ -22,3 +22,9 @@ int identity(VipsImage **out, int ushort) {
     return vips_identity(out, NULL);
   }
 }
+
+// https://libvips.github.io/libvips/API/current/libvips-create.html#vips-text
+int text(VipsImage **out, TextOptions *o) {
+  return vips_text(out, o->Text, "font", o->Font, "width", o->Width, "height", o->Height, "align", o->Align,
+  "dpi", o->DPI, "rgba", o->RGBA, "justify", o->Justify, "spacing", o->Spacing, "wrap", o->Wrap, NULL);
+}

vips/create.go

@@ -2,6 +2,35 @@ package vips
 
 // #include "create.h"
 import "C"
+import "unsafe"
+
+type TextWrap int
+
+type TextParams struct {
+	Text      string
+	Font      string
+	Width     int
+	Height    int
+	Alignment Align
+	DPI       int
+	RGBA      bool
+	Justify   bool
+	Spacing   int
+	Wrap      TextWrap
+}
+
+type vipsTextOptions struct {
+	Text      *C.char
+	Font      *C.char
+	Width     C.int
+	Height    C.int
+	DPI       C.int
+	RGBA      C.gboolean
+	Justify   C.gboolean
+	Spacing   C.int
+	Alignment C.VipsAlign
+	Wrap      C.VipsTextWrap
+}
 
 // https://libvips.github.io/libvips/API/current/libvips-create.html#vips-xyz
 func vipsXYZ(width int, height int) (*C.VipsImage, error) {
@@ -35,3 +64,48 @@ func vipsIdentity(ushort bool) (*C.VipsImage, error) {
 
 	return out, nil
 }
+
+// TextWrap enum
+const (
+	TextWrapWord     TextWrap = C.VIPS_TEXT_WRAP_WORD
+	TextWrapChar     TextWrap = C.VIPS_TEXT_WRAP_CHAR
+	TextWrapWordChar TextWrap = C.VIPS_TEXT_WRAP_WORD_CHAR
+	TextWrapNone     TextWrap = C.VIPS_TEXT_WRAP_NONE
+)
+
+// https://libvips.github.io/libvips/API/current/libvips-create.html#vips-text
+func vipsText(params *TextParams) (*C.VipsImage, error) {
+	var out *C.VipsImage
+
+	text := C.CString(params.Text)
+	defer freeCString(text)
+
+	font := C.CString(params.Font)
+	defer freeCString(font)
+
+	opts := vipsTextOptions{
+		Text:      text,
+		Font:      font,
+		Width:     C.int(params.Width),
+		Height:    C.int(params.Height),
+		DPI:       C.int(params.DPI),
+		Alignment: C.VipsAlign(params.Alignment),
+		Spacing:   C.int(params.Spacing),
+		Wrap:      C.VipsTextWrap(params.Wrap),
+	}
+
+	if params.RGBA {
+		opts.RGBA = C.TRUE
+	}
+
+	if params.Justify {
+		opts.Justify = C.TRUE
+	}
+
+	err := C.text(&out, (*C.TextOptions)(unsafe.Pointer(&opts)))
+	if err != 0 {
+		return nil, handleImageError(out)
+	}
+
+	return out, nil
+}

vips/create.h

@@ -6,7 +6,20 @@
 #include <vips/vips.h>
 #include <vips/foreign.h>
 // clang-format on
+typedef struct {
+  const char *Text;
+  const char *Font;
+  int Width;
+  int Height;
+  int DPI;
+  gboolean RGBA;
+  gboolean Justify;
+  int Spacing;
+  VipsAlign Align;
+  VipsTextWrap Wrap;
+} TextOptions;
 
 int xyz(VipsImage **out, int width, int height);
 int black(VipsImage **out, int width, int height);
 int identity(VipsImage **out, int ushort);
+int text(VipsImage **out, TextOptions *o);

vips/image.go

@@ -590,6 +590,12 @@ func Black(width, height int) (*ImageRef, error) {
 	return imageRef, err
 }
 
+// Text draws the string text to an image.
+func Text(params *TextParams) (*ImageRef, error) {
+	img, err := vipsText(params)
+	return newImageRef(img, ImageTypeUnknown, ImageTypeUnknown, nil), err
+}
+
 func newImageRef(vipsImage *C.VipsImage, currentFormat ImageType, originalFormat ImageType, buf []byte) *ImageRef {
 	imageRef := &ImageRef{
 		image:          vipsImage,

vips/image_test.go

@@ -1238,6 +1238,38 @@ func TestImageRef_Background(t *testing.T) {
 	require.Equal(t, 3, len(background))
 }
 
+func Test_MakeTextImage(t *testing.T) {
+	Startup(nil)
+
+	textImage, err := Text(&TextParams{
+		Text:      "Test",
+		Font:      "Helvetica",
+		Width:     10,
+		Height:    10,
+		Alignment: AlignLow,
+		DPI:       72,
+		Wrap:      TextWrapWord,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, textImage)
+
+	// pango Image
+	pangoText := "<span font_desc='Helvetica' font_size='13pt' foreground='black'>Test</span>"
+	pangoTextImage, err := Text(&TextParams{
+		Text:      pangoText,
+		Width:     10,
+		Height:    0,
+		Alignment: AlignLow,
+		DPI:       72,
+		RGBA:      true,
+		Justify:   false,
+		Spacing:   0,
+		Wrap:      TextWrapWord,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, pangoTextImage)
+}
+
 // TODO unit tests to cover:
 // NewImageFromReader failing test
 // NewImageFromFile failing test

vips/label.c

@@ -1,11 +1,5 @@
 #include "label.h"
 
-int text(VipsImage **out, const char *text, const char *font, int width,
-         int height, VipsAlign align, int dpi) {
-  return vips_text(out, text, "font", font, "width", width, "height", height,
-                   "align", align, "dpi", dpi, NULL);
-}
-
 int label(VipsImage *in, VipsImage **out, LabelOptions *o) {
   double ones[3] = {1, 1, 1};
   VipsImage *base = vips_image_new();

vips/label.h

@@ -16,6 +16,3 @@ typedef struct {
 } LabelOptions;
 
 int label(VipsImage *in, VipsImage **out, LabelOptions *o);
-
-int text(VipsImage **out, const char *text, const char *font, int width,
-         int height, VipsAlign align, int dpi);