Add some functions (#464)

* add arithmetic functions * add functions which get background color * add/revise vips_text function * add Min function --------- Co-authored-by: steve.3282 <[email protected]>
davidbyttow · Feb 27, 2025 · 0d82957 · 0d82957
1 parent 8d9c549
commit 0d82957
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Showing 14 changed files with 316 additions and 11 deletions.
diff --git a/vips/arithmetic.c b/vips/arithmetic.c
@@ -69,3 +69,19 @@ int hist_norm(VipsImage *in, VipsImage **out) {
 int hist_entropy(VipsImage *in, double *out) {
   return vips_hist_entropy(in, out, NULL);
 }
+
+int subtract(VipsImage *in1, VipsImage *in2, VipsImage **out) {
+  return vips_subtract(in1, in2, out, NULL);
+}
+
+int absOp(VipsImage *img, VipsImage **out) {
+  return vips_abs(img, out, NULL);
+}
+
+int project(VipsImage *in, VipsImage **col, VipsImage **row) {
+  return vips_project(in, col, row, NULL);
+}
+
+int minOp(VipsImage *in, double *out, int *x, int *y, int size) {
+  return vips_min(in, out, "x", x, "y", y, "size", size, NULL);
+}
diff --git a/vips/arithmetic.go b/vips/arithmetic.go
@@ -174,3 +174,50 @@ func vipsHistEntropy(in *C.VipsImage) (float64, error) {
 
 	return float64(out), nil
 }
+
+// https://www.libvips.org/API/current/libvips-arithmetic.html#vips-subtract
+func vipsSubtract(in1 *C.VipsImage, in2 *C.VipsImage) (*C.VipsImage, error) {
+	incOpCounter("subtract")
+	var out *C.VipsImage
+
+	if err := C.subtract(in1, in2, &out); err != 0 {
+		return nil, handleImageError(out)
+	}
+
+	return out, nil
+}
+
+// https://www.libvips.org/API/current/libvips-arithmetic.html#vips-abs
+func vipsAbs(img *C.VipsImage) (*C.VipsImage, error) {
+	incOpCounter("abs")
+	var out *C.VipsImage
+	if err := C.absOp(img, &out); err != 0 {
+		return nil, handleImageError(out)
+	}
+
+	return out, nil
+}
+
+// https://www.libvips.org/API/current/libvips-arithmetic.html#vips-project
+func vipsProject(in *C.VipsImage) (*C.VipsImage, *C.VipsImage, error) {
+	incOpCounter("project")
+	var col, row *C.VipsImage
+
+	if err := C.project(in, &col, &row); err != 0 {
+		return nil, nil, handleVipsError()
+	}
+	return col, row, nil
+}
+
+// https://www.libvips.org/API/current/libvips-arithmetic.html#vips-min
+func vipsMin(in *C.VipsImage) (float64, int, int, error) {
+	incOpCounter("min")
+	var out C.double
+	var x, y C.int
+
+	if err := C.minOp(in, &out, &x, &y, C.int(1)); err != 0 {
+		return 0, 0, 0, handleVipsError()
+	}
+
+	return float64(out), int(x), int(y), nil
+}
diff --git a/vips/arithmetic.h b/vips/arithmetic.h
@@ -18,3 +18,7 @@ int hist_find(VipsImage *in, VipsImage **out);
 int hist_cum(VipsImage *in, VipsImage **out);
 int hist_norm(VipsImage *in, VipsImage **out);
 int hist_entropy(VipsImage *in, double *out);
+int subtract(VipsImage *in1, VipsImage *in2, VipsImage **out);
+int absOp(VipsImage *img, VipsImage **out);
+int project(VipsImage *in, VipsImage **col, VipsImage **row);
+int minOp(VipsImage *in, double *out, int *x, int *y, int size);
diff --git a/vips/create.c b/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);
+}
diff --git a/vips/create.go b/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
+}
diff --git a/vips/create.h b/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);
diff --git a/vips/header.c b/vips/header.c
@@ -79,6 +79,10 @@ int get_meta_loader(const VipsImage *in, const char **out) {
   return vips_image_get_string(in, VIPS_META_LOADER, out);
 }
 
+int get_background(VipsImage *in, double **out, int *n) {
+  return vips_image_get_array_double(in, "background", out, n);
+}
+
 int get_image_delay(VipsImage *in, int **out) {
   return vips_image_get_array_int(in, "delay", out, NULL);
 }
@@ -119,4 +123,4 @@ unsigned long image_get_blob(VipsImage *in, const char *name, const void **data,
   }
 
   return 0;
-}
+}
diff --git a/vips/header.go b/vips/header.go
@@ -149,6 +149,18 @@ func vipsImageSetDelay(in *C.VipsImage, data []C.int) error {
 	return nil
 }
 
+func vipsImageGetBackground(in *C.VipsImage) ([]float64, error) {
+	incOpCounter("imageGetBackground")
+	var out *C.double
+	var n C.int
+	defer gFreePointer(unsafe.Pointer(out))
+
+	if err := C.get_background(in, &out, &n); err != 0 {
+		return nil, handleVipsError()
+	}
+	return fromCArrayDouble(out, int(n)), nil
+}
+
 // vipsDetermineImageTypeFromMetaLoader determine the image type from vips-loader metadata
 func vipsDetermineImageTypeFromMetaLoader(in *C.VipsImage) ImageType {
 	vipsLoader, ok := vipsImageGetMetaLoader(in)

diff --git a/vips/header.h b/vips/header.h
@@ -28,6 +28,7 @@ void set_page_height(VipsImage *in, int height);
 int get_meta_loader(const VipsImage *in, const char **out);
 int get_image_delay(VipsImage *in, int **out);
 void set_image_delay(VipsImage *in, const int *array, int n);
+int get_background(VipsImage *in, double **out, int *n);
 
 void image_set_blob(VipsImage *in, const char *name, const void *data,
                     size_t dataLength);
@@ -38,4 +39,4 @@ void image_set_double(VipsImage *in, const char *name, double i);
 unsigned long image_get_double(VipsImage *in, const char *name, double *out);
 
 void image_set_int(VipsImage *in, const char *name, int i);
-unsigned long image_get_int(VipsImage *in, const char *name, int *out);
+unsigned long image_get_int(VipsImage *in, const char *name, int *out);
diff --git a/vips/image.go b/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,
@@ -827,6 +833,15 @@ func (r *ImageRef) SetPageDelay(delay []int) error {
 	return vipsImageSetDelay(r.image, data)
 }
 
+// Background get the background of image.
+func (r *ImageRef) Background() ([]float64, error) {
+	out, err := vipsImageGetBackground(r.image)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 // Export creates a byte array of the image for use.
 // The function returns a byte array that can be written to a file e.g. via os.WriteFile().
 // N.B. govips does not currently have built-in support for directly exporting to a file.
@@ -1777,6 +1792,43 @@ func (r *ImageRef) DrawRect(ink ColorRGBA, left int, top int, width int, height
 	return nil
 }
 
+// Subtract calculate subtract operation between two images.
+func (r *ImageRef) Subtract(in2 *ImageRef) error {
+	out, err := vipsSubtract(r.image, in2.image)
+	if err != nil {
+		return err
+	}
+
+	r.setImage(out)
+	return nil
+}
+
+// Abs calculate abs operation.
+func (r *ImageRef) Abs() error {
+	out, err := vipsAbs(r.image)
+	if err != nil {
+		return err
+	}
+
+	r.setImage(out)
+	return nil
+}
+
+// Project calculate project operation.
+func (r *ImageRef) Project() (*ImageRef, *ImageRef, error) {
+	col, row, err := vipsProject(r.image)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return newImageRef(col, r.format, r.originalFormat, nil), newImageRef(row, r.format, r.originalFormat, nil), nil
+}
+
+// Min finds the minimum value in an image.
+func (r *ImageRef) Min() (float64, int, int, error) {
+	return vipsMin(r.image)
+}
+
 // Rank does rank filtering on an image. A window of size width by height is passed over the image.
 // At each position, the pixels inside the window are sorted into ascending order and the pixel at position
 // index is output. index numbers from 0.

diff --git a/vips/image_test.go b/vips/image_test.go
@@ -1201,6 +1201,78 @@ func Test_NewImageFromFile(t *testing.T) {
 	assert.Equal(t, 1, image.Pages())
 }
 
+func TestImageRef_ArithmeticOperation(t *testing.T) {
+	Startup(nil)
+
+	image, err := NewImageFromFile(resources + "png-24bit.png")
+	require.NoError(t, err)
+	image2, err := NewImageFromFile(resources + "png-24bit.png")
+	require.NoError(t, err)
+
+	orgWidth := image.Width()
+	orgHeight := image.Height()
+
+	_, _, _, err = image.Min()
+	require.NoError(t, err)
+
+	err = image2.Abs()
+	require.NoError(t, err)
+
+	err = image.Subtract(image2)
+	require.NoError(t, err)
+
+	colImage, rowImage, err := image.Project()
+	require.NoError(t, err)
+
+	require.Equal(t, orgWidth, colImage.Width())
+	require.Equal(t, 1, colImage.Height())
+	require.Equal(t, 1, rowImage.Width())
+	require.Equal(t, orgHeight, rowImage.Height())
+}
+
+func TestImageRef_Background(t *testing.T) {
+	Startup(nil)
+	image, err := NewImageFromFile(resources + "gif-animated.gif")
+	require.NoError(t, err)
+
+	background, err := image.Background()
+	require.NoError(t, err)
+
+	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