From 81a7656c8c245cbe9a008dbfb7fa9a0a3e9152e2 Mon Sep 17 00:00:00 2001
From: Aurele Boquet <aurele.boquet@gmail.com>
Date: Fri, 18 Sep 2026 16:11:37 +0200
Subject: [PATCH] fix(iv): 'save window' saves only the visible region

Signed-off-by: Aurele Boquet <aurele.boquet@gmail.com>
---
 src/iv/imageviewer.cpp | 23 +++++++++++++++++++++--
 src/iv/ivgl.cpp        | 35 +++++++++++++++++++++++++++++++++++
 src/iv/ivgl.h          |  4 ++++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/src/iv/imageviewer.cpp b/src/iv/imageviewer.cpp
index 3f88b4b9d6..130ee56ba2 100644
--- a/src/iv/imageviewer.cpp
+++ b/src/iv/imageviewer.cpp
@@ -41,6 +41,7 @@
 #include <OpenImageIO/color.h>
 #include <OpenImageIO/dassert.h>
 #include <OpenImageIO/filesystem.h>
+#include <OpenImageIO/imagebufalgo.h>
 #include <OpenImageIO/imagecache.h>
 #include <OpenImageIO/strutil.h>
 #include <OpenImageIO/sysutil.h>
@@ -1104,13 +1105,31 @@ ImageViewer::saveWindowAs()
     IvImage* img = cur();
     if (!img)
         return;
+    ROI roi;
+    glwin->get_visible_image_roi(roi);
+    if (!roi.defined() || roi.width() <= 0 || roi.height() <= 0) {
+        // TODO: May not be visible. This should be replaced with a GUI dialog.
+        OIIO::print(stderr,
+                    "Save failed: no pixels of the image are visible\n");
+        return;
+    }
     QString name;
     name = QFileDialog::getSaveFileName(this, tr("Save Window"),
                                         QString(img->uname().c_str()));
     if (name.isEmpty())
         return;
-    img->write(name.toStdString(), TypeUnknown, "", image_progress_callback,
-               this);
+    ImageBuf cropped;
+    if (!ImageBufAlgo::cut(cropped, *img, roi)) {
+        // TODO: May not be visible. This should be replaced with a GUI dialog.
+        OIIO::print(stderr, "Crop failed: {}\n", cropped.geterror());
+        return;
+    }
+    bool ok = cropped.write(name.toStdString(), TypeUnknown, "",
+                            image_progress_callback, this);
+    if (!ok) {
+        // TODO: May not be visible. This should be replaced with a GUI dialog.
+        OIIO::print(stderr, "Save failed: {}\n", cropped.geterror());
+    }
 }
 
 
diff --git a/src/iv/ivgl.cpp b/src/iv/ivgl.cpp
index 145a772808..562b023dce 100644
--- a/src/iv/ivgl.cpp
+++ b/src/iv/ivgl.cpp
@@ -2186,6 +2186,41 @@ IvGL::get_given_image_pixel(int& x, int& y, int mouseX, int mouseY)
 
 
 
+void
+IvGL::get_visible_image_roi(ROI& roi)
+{
+    roi          = ROI();
+    IvImage* img = m_slots[0].image;
+    if (!img || !img->image_valid())
+        return;
+    const ImageSpec& spec(img->spec());
+
+    // The two opposite corners of the viewport, in image pixel coordinates
+    int x0, y0, x1, y1;
+    get_given_image_pixel(x0, y0, 0, 0);
+    get_given_image_pixel(x1, y1, width() - 1, height() - 1);
+
+    // Rotating or flipping the display may send the corners anywhere, so map
+    // both of them and then sort out which is the min and which is the max.
+    float scale_x = 1.0f, scale_y = 1.0f, rotate_z = 0.0f;
+    float x0_img = x0, y0_img = y0, x1_img = x1, y1_img = y1;
+    handle_orientation(img->orientation(), spec.width, spec.height, scale_x,
+                       scale_y, rotate_z, x0_img, y0_img, true);
+    handle_orientation(img->orientation(), spec.width, spec.height, scale_x,
+                       scale_y, rotate_z, x1_img, y1_img, true);
+
+    ROI visible((int)floorf(std::min(x0_img, x1_img)),
+                (int)floorf(std::max(x0_img, x1_img)) + 1,
+                (int)floorf(std::min(y0_img, y1_img)),
+                (int)floorf(std::max(y0_img, y1_img)) + 1, 0, 1, 0,
+                spec.nchannels);
+
+    // The window may show more than the image, so keep only real pixels.
+    roi = roi_intersection(visible, img->roi());
+}
+
+
+
 void
 IvGL::get_focus_image_pixel(int& x, int& y)
 {
diff --git a/src/iv/ivgl.h b/src/iv/ivgl.h
index 645b6ab9fc..631db58d16 100644
--- a/src/iv/ivgl.h
+++ b/src/iv/ivgl.h
@@ -87,6 +87,10 @@ class IvGL : public QOpenGLWidget, protected QOpenGLExtraFunctions {
     ///
     void get_given_image_pixel(int& x, int& y, int mouseX, int mouseY);
 
+    /// Which region of the current image is currently visible in the
+    /// viewport?
+    void get_visible_image_roi(ROI& roi);
+
     /// What are the min/max/avg values of each channel in the selected area?
     void update_area_probe_text();