From 59c2e8906a5cb64b55f29d656a5a27366ace38a0 Mon Sep 17 00:00:00 2001
From: "Daniel J. Ramirez" <djrmuv@gmail.com>
Date: Fri, 17 Nov 2017 21:42:14 -0600
Subject: [PATCH] Improved packed scene previews.

---
 core/image.cpp         | 23 ++++++++++++++++-------
 core/image.h           |  1 +
 editor/editor_node.cpp | 34 ++++++++++++++++++++--------------
 3 files changed, 37 insertions(+), 21 deletions(-)

diff --git a/core/image.cpp b/core/image.cpp
index 42684e7ea73..422c0e407b0 100644
--- a/core/image.cpp
+++ b/core/image.cpp
@@ -757,22 +757,24 @@ void Image::resize(int p_width, int p_height, Interpolation p_interpolation) {
 
 	_copy_internals_from(dst);
 }
-void Image::crop(int p_width, int p_height) {
 
+void Image::crop_from_point(int p_x, int p_y, int p_width, int p_height) {
 	if (!_can_modify(format)) {
 		ERR_EXPLAIN("Cannot crop in indexed, compressed or custom image formats.");
 		ERR_FAIL();
 	}
+	ERR_FAIL_COND(p_x < 0);
+	ERR_FAIL_COND(p_y < 0);
 	ERR_FAIL_COND(p_width <= 0);
 	ERR_FAIL_COND(p_height <= 0);
-	ERR_FAIL_COND(p_width > MAX_WIDTH);
-	ERR_FAIL_COND(p_height > MAX_HEIGHT);
+	ERR_FAIL_COND(p_x + p_width > MAX_WIDTH);
+	ERR_FAIL_COND(p_y + p_height > MAX_HEIGHT);
 
 	/* to save memory, cropping should be done in-place, however, since this function
 	   will most likely either not be used much, or in critical areas, for now it wont, because
 	   it's a waste of time. */
 
-	if (p_width == width && p_height == height)
+	if (p_width == width && p_height == height && p_x == 0 && p_y == 0)
 		return;
 
 	uint8_t pdata[16]; //largest is 16
@@ -784,9 +786,11 @@ void Image::crop(int p_width, int p_height) {
 		PoolVector<uint8_t>::Read r = data.read();
 		PoolVector<uint8_t>::Write w = dst.data.write();
 
-		for (int y = 0; y < p_height; y++) {
+		int m_h = p_y + p_height;
+		int m_w = p_x + p_width;
+		for (int y = p_y; y < m_h; y++) {
 
-			for (int x = 0; x < p_width; x++) {
+			for (int x = p_x; x < m_w; x++) {
 
 				if ((x >= width || y >= height)) {
 					for (uint32_t i = 0; i < pixel_size; i++)
@@ -795,7 +799,7 @@ void Image::crop(int p_width, int p_height) {
 					_get_pixelb(x, y, pixel_size, r.ptr(), pdata);
 				}
 
-				dst._put_pixelb(x, y, pixel_size, w.ptr(), pdata);
+				dst._put_pixelb(x - p_x, y - p_y, pixel_size, w.ptr(), pdata);
 			}
 		}
 	}
@@ -805,6 +809,11 @@ void Image::crop(int p_width, int p_height) {
 	_copy_internals_from(dst);
 }
 
+void Image::crop(int p_width, int p_height) {
+
+	crop_from_point(0, 0, p_width, p_height);
+}
+
 void Image::flip_y() {
 
 	if (!_can_modify(format)) {
diff --git a/core/image.h b/core/image.h
index 27df65a8989..24693aa7064 100644
--- a/core/image.h
+++ b/core/image.h
@@ -207,6 +207,7 @@ public:
 	/**
 	 * Crop the image to a specific size, if larger, then the image is filled by black
 	 */
+	void crop_from_point(int p_x, int p_y, int p_width, int p_height);
 	void crop(int p_width, int p_height);
 
 	void flip_x();
diff --git a/editor/editor_node.cpp b/editor/editor_node.cpp
index 777aedefd27..0cec380fc1f 100644
--- a/editor/editor_node.cpp
+++ b/editor/editor_node.cpp
@@ -906,23 +906,29 @@ void EditorNode::_save_scene_with_preview(String p_file, int p_idx) {
 
 		int preview_size = EditorSettings::get_singleton()->get("filesystem/file_dialog/thumbnail_size");
 		preview_size *= EDSCALE;
-		int width, height;
-		if (img->get_width() > preview_size && img->get_width() >= img->get_height()) {
 
-			width = preview_size;
-			height = img->get_height() * preview_size / img->get_width();
-		} else if (img->get_height() > preview_size && img->get_height() >= img->get_width()) {
-
-			height = preview_size;
-			width = img->get_width() * preview_size / img->get_height();
-		} else {
-
-			width = img->get_width();
-			height = img->get_height();
-		}
+		// consider a square region
+		int vp_size = MIN(img->get_width(), img->get_height());
+		int x = (img->get_width() - vp_size) / 2;
+		int y = (img->get_height() - vp_size) / 2;
 
 		img->convert(Image::FORMAT_RGB8);
-		img->resize(width, height);
+
+		if (vp_size < preview_size) {
+			// just square it.
+			img->crop_from_point(x, y, vp_size, vp_size);
+		} else {
+			int ratio = vp_size / preview_size;
+			int size = preview_size * (ratio / 2);
+
+			x = (img->get_width() - size) / 2;
+			y = (img->get_height() - size) / 2;
+
+			img->crop_from_point(x, y, size, size);
+			// We could get better pictures with better filters
+			img->resize(preview_size, preview_size, Image::INTERPOLATE_CUBIC);
+		}
+
 		img->flip_y();
 
 		//save thumbnail directly, as thumbnailer may not update due to actual scene not changing md5