From 75637c239751c35bb71b5c0e2068b2a04fd48a66 Mon Sep 17 00:00:00 2001
From: songjiayang <songjiayang1@gmail.com>
Date: Mon, 23 Oct 2023 02:30:29 +0800
Subject: [PATCH] Fixed the bug of incorrect calculation of page height when
 resize gif with vscale (#386)

Signed-off-by: songjiayang <songjiayang1@gmail.com>
---
 vips/arithmetic.go     |  4 ++--
 vips/color.go          |  2 +-
 vips/image.go          |  2 +-
 vips/image_gif_test.go | 13 +++++++++++++
 vips/logging.go        |  1 +
 5 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/vips/arithmetic.go b/vips/arithmetic.go
index f2bda66d..2a2d25c0 100644
--- a/vips/arithmetic.go
+++ b/vips/arithmetic.go
@@ -40,7 +40,7 @@ func vipsDivide(left *C.VipsImage, right *C.VipsImage) (*C.VipsImage, error) {
 	return out, nil
 }
 
-//  https://libvips.github.io/libvips/API/current/libvips-arithmetic.html#vips-linear
+// https://libvips.github.io/libvips/API/current/libvips-arithmetic.html#vips-linear
 func vipsLinear(in *C.VipsImage, a, b []float64, n int) (*C.VipsImage, error) {
 	incOpCounter("linear")
 	var out *C.VipsImage
@@ -52,7 +52,7 @@ func vipsLinear(in *C.VipsImage, a, b []float64, n int) (*C.VipsImage, error) {
 	return out, nil
 }
 
-//  https://libvips.github.io/libvips/API/current/libvips-arithmetic.html#vips-linear1
+// https://libvips.github.io/libvips/API/current/libvips-arithmetic.html#vips-linear1
 func vipsLinear1(in *C.VipsImage, a, b float64) (*C.VipsImage, error) {
 	incOpCounter("linear1")
 	var out *C.VipsImage
diff --git a/vips/color.go b/vips/color.go
index def51aca..df5aed52 100644
--- a/vips/color.go
+++ b/vips/color.go
@@ -43,7 +43,7 @@ const (
 // Intent represents VIPS_INTENT type
 type Intent int
 
-//Intent enum
+// Intent enum
 const (
 	IntentPerceptual Intent = C.VIPS_INTENT_PERCEPTUAL
 	IntentRelative   Intent = C.VIPS_INTENT_RELATIVE
diff --git a/vips/image.go b/vips/image.go
index fa6cd0c4..429ddd30 100644
--- a/vips/image.go
+++ b/vips/image.go
@@ -1662,7 +1662,7 @@ func (r *ImageRef) ResizeWithVScale(hScale, vScale float64, kernel Kernel) error
 		if vScale != -1 {
 			scale = vScale
 		}
-		newPageHeight := int(float64(pageHeight) * scale)
+		newPageHeight := int(float64(pageHeight)*scale + 0.5)
 		if err := r.SetPageHeight(newPageHeight); err != nil {
 			return err
 		}
diff --git a/vips/image_gif_test.go b/vips/image_gif_test.go
index 7b1e8eee..169103d2 100644
--- a/vips/image_gif_test.go
+++ b/vips/image_gif_test.go
@@ -50,6 +50,19 @@ func TestImage_GIF_Animated_Resize(t *testing.T) {
 		nil)
 }
 
+func TestImage_GIF_Animated_ResizeWithVScale(t *testing.T) {
+	goldenAnimatedTest(t, resources+"gif-animated.gif",
+		3,
+		func(img *ImageRef) error {
+			return img.ResizeWithVScale(0.5, 0.78, KernelCubic)
+		},
+		func(img *ImageRef) {
+			assert.Equal(t, 3, img.Pages())
+			assert.Equal(t, 100, img.GetPageHeight())
+		},
+		nil)
+}
+
 func TestImage_GIF_Animated_Rotate90(t *testing.T) {
 	goldenAnimatedTest(t, resources+"gif-animated.gif",
 		-1,
diff --git a/vips/logging.go b/vips/logging.go
index 7822acaf..5053d016 100644
--- a/vips/logging.go
+++ b/vips/logging.go
@@ -33,6 +33,7 @@ var (
 // and called by glib and libvips for each logging message. It will call govipsLog
 // which in turn will filter based on verbosity and direct the messages to the
 // currently chosen LoggingHandlerFunction.
+//
 //export govipsLoggingHandler
 func govipsLoggingHandler(messageDomain *C.char, messageLevel C.int, message *C.char) {
 	govipsLog(C.GoString(messageDomain), LogLevel(messageLevel), C.GoString(message))