From 9f25f7fced5920e2925f8065b6677e0434ffc673 Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Sat, 12 Jun 2021 19:06:32 +1000
Subject: [PATCH] [client] main: display error when the frame has been
 truncated

---
 client/src/main.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/client/src/main.c b/client/src/main.c
index 0fd6d80f..671ede9a 100644
--- a/client/src/main.c
+++ b/client/src/main.c
@@ -34,6 +34,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <assert.h>
+#include <math.h>
 #include <stdatomic.h>
 #include <linux/input.h>
 
@@ -428,6 +429,23 @@ int main_frameThread(void * unused)
       lgrFormat.stride = frame->stride;
       lgrFormat.pitch  = frame->pitch;
 
+      if (frame->height != frame->realHeight)
+      {
+        const float needed =
+          ((frame->realHeight * frame->pitch * 2) / 1048576.0f) + 10.0f;
+        const int   size   = (int)powf(2.0f, ceilf(logf(needed) / logf(2.0f)));
+
+        DEBUG_BREAK();
+        DEBUG_WARN("IVSHMEM too small, screen truncated");
+        DEBUG_WARN("Recommend increase size to %d MiB", size);
+        DEBUG_BREAK();
+
+        app_alert(LG_ALERT_ERROR,
+          "IVSHMEM too small, screen truncated\n"
+          "Recommend increasing size to %d MiB",
+          size);
+      }
+
       switch(frame->rotation)
       {
         case FRAME_ROT_0  : lgrFormat.rotate = LG_ROTATE_0  ; break;