commit 49d6206ca398ea38f734d67c1004a125ced5f170
author Praveena Pachipulusu <pveena@codeaurora.org> Fri Jun 06 19:22:23 2014 +0530
committer Praveena Pachipulusu <pveena@codeaurora.org> Tue Jun 10 11:50:38 2014 +0530
tree 72e3251fe15487ba41743c0a19455be5d1c1a791
parent 76967610715eae28c48d25866d6776d12f42e842

hwc: Calculate DPI values according to changed resolution

If dynamic FB feature is enabled, calculate xdpi, ydpi
values based on new resolution.

Change-Id: Icbc8d2161082f60983532d1a57d9142653c65e9a

libhwcomposer/hwc_utils.cpp

diff --git a/libhwcomposer/hwc_utils.cpp b/libhwcomposer/hwc_utils.cpp
index 4708368..77d9312 100644
--- a/libhwcomposer/hwc_utils.cpp
+++ b/libhwcomposer/hwc_utils.cpp
@@ -83,7 +83,8 @@
             (xres < MIN_DISPLAY_XRES || yres < MIN_DISPLAY_YRES));
 }
 
-void changeResolution(hwc_context_t *ctx, int xres_orig, int yres_orig) {
+void changeResolution(hwc_context_t *ctx, int xres_orig, int yres_orig,
+                      int width, int height) {
     //Store original display resolution.
     ctx->dpyAttr[HWC_DISPLAY_PRIMARY].xres_new = xres_orig;
     ctx->dpyAttr[HWC_DISPLAY_PRIMARY].yres_new = yres_orig;
@@ -99,6 +100,12 @@
             ctx->dpyAttr[HWC_DISPLAY_PRIMARY].xres_new = xres_new;
             ctx->dpyAttr[HWC_DISPLAY_PRIMARY].yres_new = yres_new;
             ctx->dpyAttr[HWC_DISPLAY_PRIMARY].customFBSize = true;
+
+            //Caluculate DPI according to changed resolution.
+            float xdpi = ((float)xres_new * 25.4f) / (float)width;
+            float ydpi = ((float)yres_new * 25.4f) / (float)height;
+            ctx->dpyAttr[HWC_DISPLAY_PRIMARY].xdpi = xdpi;
+            ctx->dpyAttr[HWC_DISPLAY_PRIMARY].ydpi = ydpi;
         }
     }
 }
@@ -168,7 +175,7 @@
             (uint32_t)(1000000000l / fps);
 
     //To change resolution of primary display
-    changeResolution(ctx, info.xres, info.yres);
+    changeResolution(ctx, info.xres, info.yres, info.width, info.height);
 
     //Unblank primary on first boot
     if(ioctl(fb_fd, FBIOBLANK,FB_BLANK_UNBLANK) < 0) {