From 99ddcd3d0eb5ab44116b01489d4a49d0f86e5e86 Mon Sep 17 00:00:00 2001
From: Alexander Batalov <alex.batalov@gmail.com>
Date: Mon, 23 May 2022 11:16:04 +0300
Subject: [PATCH] Fix save game preview

See #3
---
 src/loadsave.cc | 28 ++++++++++++++++++++++++----
 src/map.h       |  3 +++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/loadsave.cc b/src/loadsave.cc
index 6c754ba..baab366 100644
--- a/src/loadsave.cc
+++ b/src/loadsave.cc
@@ -623,8 +623,18 @@ int _QuickSnapShot()
         gameMouseObjectsShow();
     }
 
-    unsigned char* windowBuffer = windowGetBuffer(gIsoWindow);
-    blitBufferToBufferStretch(windowBuffer, 640, 380, 640, _snapshot, LS_PREVIEW_WIDTH, LS_PREVIEW_HEIGHT, LS_PREVIEW_WIDTH);
+    // For preview take 640x380 area in the center of isometric window.
+    unsigned char* isoWindowBuffer = windowGetBuffer(gIsoWindow)
+        + (screenGetWidth() - ORIGINAL_ISO_WINDOW_WIDTH) / 2 * (screenGetHeight() - ORIGINAL_ISO_WINDOW_HEIGHT) / 2
+        + (screenGetWidth() - ORIGINAL_ISO_WINDOW_WIDTH) / 2;
+    blitBufferToBufferStretch(isoWindowBuffer,
+        ORIGINAL_ISO_WINDOW_WIDTH,
+        ORIGINAL_ISO_WINDOW_HEIGHT,
+        windowGetWidth(gIsoWindow),
+        _snapshot,
+        LS_PREVIEW_WIDTH,
+        LS_PREVIEW_HEIGHT,
+        LS_PREVIEW_WIDTH);
 
     _snapshotBuf = _snapshot;
 
@@ -1094,8 +1104,18 @@ int lsgWindowInit(int windowType)
             gameMouseObjectsShow();
         }
 
-        unsigned char* windowBuf = windowGetBuffer(gIsoWindow);
-        blitBufferToBufferStretch(windowBuf, 640, 380, 640, _snapshotBuf, LS_PREVIEW_WIDTH, LS_PREVIEW_HEIGHT, LS_PREVIEW_WIDTH);
+        // For preview take 640x380 area in the center of isometric window.
+        unsigned char* isoWindowBuffer = windowGetBuffer(gIsoWindow)
+            + (screenGetWidth() - ORIGINAL_ISO_WINDOW_WIDTH) / 2 * (screenGetHeight() - ORIGINAL_ISO_WINDOW_HEIGHT) / 2
+            + (screenGetWidth() - ORIGINAL_ISO_WINDOW_WIDTH) / 2;
+        blitBufferToBufferStretch(isoWindowBuffer,
+            ORIGINAL_ISO_WINDOW_WIDTH,
+            ORIGINAL_ISO_WINDOW_HEIGHT,
+            windowGetWidth(gIsoWindow),
+            _snapshotBuf,
+            LS_PREVIEW_WIDTH,
+            LS_PREVIEW_HEIGHT,
+            LS_PREVIEW_WIDTH);
     }
 
     for (int index = 0; index < LOAD_SAVE_FRM_COUNT; index++) {
diff --git a/src/map.h b/src/map.h
index a544ac1..0f8a278 100644
--- a/src/map.h
+++ b/src/map.h
@@ -12,6 +12,9 @@
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 
+#define ORIGINAL_ISO_WINDOW_WIDTH 640
+#define ORIGINAL_ISO_WINDOW_HEIGHT 380
+
 // TODO: Probably not needed -> replace with array?
 typedef struct TileData {
     int field_0[SQUARE_GRID_SIZE];