diff --git a/src/lib/evas/canvas/efl_canvas_image.c b/src/lib/evas/canvas/efl_canvas_image.c
index ee32e61697..73bffcec61 100644
--- a/src/lib/evas/canvas/efl_canvas_image.c
+++ b/src/lib/evas/canvas/efl_canvas_image.c
@@ -601,7 +601,7 @@ _image_pixels_set(Evas_Object_Protected_Data *obj,
 
    if (ENFN->image_data_maps_get)
      {
-        if (ENFN->image_data_maps_get(ENDT, o->engine_data, NULL, NULL) > 0)
+        if (ENFN->image_data_maps_get(ENDT, o->engine_data, NULL) > 0)
           {
              ERR("can not set pixels when there are open memory maps");
              return EINA_FALSE;
@@ -780,8 +780,8 @@ _efl_canvas_image_efl_gfx_buffer_buffer_map(Eo *eo_obj, void *_pd EINA_UNUSED,
 {
    Evas_Object_Protected_Data *obj = efl_data_scope_get(eo_obj, EFL_CANVAS_OBJECT_CLASS);
    Evas_Image_Data *o = efl_data_scope_get(eo_obj, EFL_CANVAS_IMAGE_INTERNAL_CLASS);
-   int len = 0, s = 0, width = 0, height = 0;
-   void *data = NULL;
+   int s = 0, width = 0, height = 0;
+   const Eina_Rw_Slice *slice = NULL;
 
    if (!ENFN->image_data_map)
      goto end; // not implemented
@@ -807,13 +807,18 @@ _efl_canvas_image_efl_gfx_buffer_buffer_map(Eo *eo_obj, void *_pd EINA_UNUSED,
         goto end;
      }
 
-   data = ENFN->image_data_map(ENDT, &o->engine_data, &len, &s, x, y, w, h, cspace, mode);
-   DBG("map(%p, %d,%d %dx%d) -> %p (%d bytes)", eo_obj, x, y, w, h, data, len);
+   slice = ENFN->image_data_map(ENDT, &o->engine_data, &s, x, y, w, h, cspace, mode);
+   if (slice)
+     {
+        DBG("map(%p, %d,%d %dx%d) -> %p (%zu bytes)", eo_obj, x, y, w, h,
+            slice->mem, slice->len);
+     }
+   else DBG("map(%p, %d,%d %dx%d) -> (null)", eo_obj, x, y, w, h);
 
 end:
-   if (length) *length = len;
+   if (length) *length = slice->len;
    if (stride) *stride = s;
-   return data;
+   return slice->mem;
 }
 
 EOLIAN static Eina_Bool
@@ -822,11 +827,14 @@ _efl_canvas_image_efl_gfx_buffer_buffer_unmap(Eo *eo_obj, void *_pd EINA_UNUSED,
 {
    Evas_Object_Protected_Data *obj = efl_data_scope_get(eo_obj, EFL_CANVAS_OBJECT_CLASS);
    Evas_Image_Data *o = efl_data_scope_get(eo_obj, EFL_CANVAS_IMAGE_INTERNAL_CLASS);
+   Eina_Rw_Slice slice;
 
    if (!ENFN->image_data_unmap || !o->engine_data)
      return EINA_FALSE;
 
-   if (!ENFN->image_data_unmap(ENDT, o->engine_data, data, length))
+   slice.mem = data;
+   slice.len = length;
+   if (!ENFN->image_data_unmap(ENDT, o->engine_data, &slice))
      return EINA_FALSE;
 
    return EINA_TRUE;
diff --git a/src/lib/evas/canvas/efl_canvas_proxy.c b/src/lib/evas/canvas/efl_canvas_proxy.c
index 47f5a0158e..f0562e2d26 100644
--- a/src/lib/evas/canvas/efl_canvas_proxy.c
+++ b/src/lib/evas/canvas/efl_canvas_proxy.c
@@ -269,6 +269,7 @@ _efl_canvas_proxy_efl_gfx_buffer_buffer_map(Eo *eo_obj, void *_pd EINA_UNUSED,
    Evas_Object_Protected_Data *obj = efl_data_scope_get(eo_obj, EFL_CANVAS_OBJECT_CLASS);
    Evas_Image_Data *o = efl_data_scope_get(eo_obj, EFL_CANVAS_IMAGE_INTERNAL_CLASS);
    int len = 0, s = 0, width = 0, height = 0;
+   const Eina_Rw_Slice *slice = NULL;
    void *image, *data = NULL;
 
    if (!ENFN->image_data_map)
@@ -302,8 +303,13 @@ _efl_canvas_proxy_efl_gfx_buffer_buffer_map(Eo *eo_obj, void *_pd EINA_UNUSED,
         goto end;
      }
 
-   data = ENFN->image_data_map(ENDT, &image, &len, &s, x, y, w, h, cspace, mode);
-   DBG("map(%p, %d,%d %dx%d) -> %p (%d bytes)", eo_obj, x, y, w, h, data, len);
+   slice = ENFN->image_data_map(ENDT, &image, &s, x, y, w, h, cspace, mode);
+   if (slice)
+     {
+        DBG("map(%p, %d,%d %dx%d) -> %p (%zu bytes)", eo_obj, x, y, w, h,
+            slice->mem, slice->len);
+     }
+   else DBG("map(%p, %d,%d %dx%d) -> (null)", eo_obj, x, y, w, h);
 
 end:
    if (length) *length = len;
@@ -317,11 +323,14 @@ _efl_canvas_proxy_efl_gfx_buffer_buffer_unmap(Eo *eo_obj, void *_pd EINA_UNUSED,
 {
    Evas_Object_Protected_Data *obj = efl_data_scope_get(eo_obj, EFL_CANVAS_OBJECT_CLASS);
    Evas_Image_Data *o = efl_data_scope_get(eo_obj, EFL_CANVAS_IMAGE_INTERNAL_CLASS);
+   Eina_Rw_Slice slice;
 
    if (!ENFN->image_data_unmap || !o->engine_data)
      return EINA_FALSE;
 
-   if (!ENFN->image_data_unmap(ENDT, o->engine_data, data, length))
+   slice.mem = data;
+   slice.len = length;
+   if (!ENFN->image_data_unmap(ENDT, o->engine_data, &slice))
      return EINA_FALSE;
 
    return EINA_TRUE;
diff --git a/src/lib/evas/include/evas_common_private.h b/src/lib/evas/include/evas_common_private.h
index 77158ab434..8d66ad87f7 100644
--- a/src/lib/evas/include/evas_common_private.h
+++ b/src/lib/evas/include/evas_common_private.h
@@ -840,8 +840,9 @@ struct _RGBA_Pipe_Thread_Info
 
 struct _RGBA_Image_Data_Map {
    EINA_INLIST;
-   unsigned char  *ptr, *baseptr;
-   int             size, stride; // in bytes
+   unsigned char  *baseptr;
+   Eina_Rw_Slice   slice;
+   int             stride; // in bytes
    int             rx, ry, rw, rh; // actual map region
    int             plane;
    Evas_Colorspace cspace;
diff --git a/src/lib/evas/include/evas_private.h b/src/lib/evas/include/evas_private.h
index 845c7c41f9..7e4c2e4acd 100644
--- a/src/lib/evas/include/evas_private.h
+++ b/src/lib/evas/include/evas_private.h
@@ -1369,9 +1369,9 @@ struct _Evas_Func
    Eina_Bool (*image_can_region_get)       (void *data, void *image);
 
    /* image data map/unmap: direct or indirect access to pixels data */
-   void *(*image_data_map)                 (void *data, void **image, int *length, int *stride, int x, int y, int w, int h, Evas_Colorspace cspace, Efl_Gfx_Buffer_Access_Mode mode);
-   Eina_Bool (*image_data_unmap)           (void *data, void *image, void *map, int length);
-   int (*image_data_maps_get)              (void *data, const void *image, void **maps, int *lengths);
+   const Eina_Rw_Slice *(*image_data_map)  (void *data, void **image, int *stride, int x, int y, int w, int h, Evas_Colorspace cspace, Efl_Gfx_Buffer_Access_Mode mode);
+   Eina_Bool (*image_data_unmap)           (void *data, void *image, const Eina_Rw_Slice *slice);
+   int (*image_data_maps_get)              (void *data, const void *image, const Eina_Rw_Slice **slices);
 
    int (*image_native_init)                (void *data, Evas_Native_Surface_Type type);
    void (*image_native_shutdown)           (void *data, Evas_Native_Surface_Type type);
diff --git a/src/modules/evas/engines/gl_common/evas_gl_common.h b/src/modules/evas/engines/gl_common/evas_gl_common.h
index c390e3370b..23eddef590 100644
--- a/src/modules/evas/engines/gl_common/evas_gl_common.h
+++ b/src/modules/evas/engines/gl_common/evas_gl_common.h
@@ -491,8 +491,8 @@ struct _Evas_GL_Image_Data_Map
    EINA_INLIST;
    Evas_GL_Texture *tex; // one or the other
    RGBA_Image      *im; // one or the other
-   unsigned char   *ptr;
-   int              size, stride; // in bytes
+   Eina_Rw_Slice    slice;
+   int              stride; // in bytes
    int              rx, ry, rw, rh; // actual map region
    Evas_Colorspace  cspace;
    Efl_Gfx_Buffer_Access_Mode mode;
diff --git a/src/modules/evas/engines/gl_generic/evas_engine.c b/src/modules/evas/engines/gl_generic/evas_engine.c
index b6e08afcc8..e48dd259c7 100644
--- a/src/modules/evas/engines/gl_generic/evas_engine.c
+++ b/src/modules/evas/engines/gl_generic/evas_engine.c
@@ -2794,16 +2794,15 @@ eng_ector_end(void *data, void *context EINA_UNUSED, Ector_Surface *ector,
      }
 }
 
-static void *
+static const Eina_Rw_Slice *
 eng_image_data_map(void *engdata EINA_UNUSED, void **image,
-                   int *length, int *stride,
-                   int x, int y, int w, int h,
+                   int *stride, int x, int y, int w, int h,
                    Evas_Colorspace cspace, Efl_Gfx_Buffer_Access_Mode mode)
 {
    Eina_Bool cow = EINA_FALSE, to_write = EINA_FALSE;
    Evas_GL_Image_Data_Map *map = NULL;
+   const Eina_Rw_Slice *slice = NULL;
    Evas_GL_Image *im;
-   void *ret;
 
    EINA_SAFETY_ON_FALSE_RETURN_VAL(image && *image, NULL);
    im = *image;
@@ -2816,12 +2815,12 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
 
    if (im->im)
      {
-        int len = 0, strid = 0;
+        int strid = 0;
 
         // Call sw generic implementation. Should work for simple cases.
-        ret = pfunc.image_data_map(NULL, (void **) &im->im, &len, &strid,
-                                   x, y, w, h, cspace, mode);
-        if (ret)
+        slice = pfunc.image_data_map(NULL, (void **) &im->im, &strid,
+                                     x, y, w, h, cspace, mode);
+        if (slice)
           {
              map = calloc(1, sizeof(*map));
              map->cspace = cspace;
@@ -2830,15 +2829,13 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
              map->rw = w;
              map->rh = h;
              map->mode = mode;
-             map->size = len;
+             map->slice = *slice;
              map->stride = strid;
              map->im = im->im; // ref?
-             map->ptr = ret;
              im->maps = eina_inlist_prepend(im->maps, EINA_INLIST_GET(map));
           }
-        if (length) *length = len;
         if (stride) *stride = strid;
-        return ret;
+        return &map->slice;
      }
 
    // TODO: glReadPixels from FBO if possible
@@ -2847,22 +2844,22 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
 }
 
 static Eina_Bool
-eng_image_data_unmap(void *engdata EINA_UNUSED, void *image, void *memory, int length)
+eng_image_data_unmap(void *engdata EINA_UNUSED, void *image, const Eina_Rw_Slice *slice)
 {
    Evas_GL_Image_Data_Map *map;
    Evas_GL_Image *im = image;
    Eina_Bool found = EINA_FALSE;
 
-   if (!im || !memory)
+   if (!im || !slice)
      return EINA_FALSE;
 
    EINA_INLIST_FOREACH(im->maps, map)
      {
-        if ((map->ptr == memory) && (map->size == length))
+        if ((map->slice.len == slice->len) && (map->slice.mem == slice->mem))
           {
              found = EINA_TRUE;
              if (map->im)
-               found = pfunc.image_data_unmap(NULL, map->im, memory, length);
+               found = pfunc.image_data_unmap(NULL, map->im, slice);
              if (found)
                {
                   if (im->im && im->tex &&
@@ -2875,12 +2872,12 @@ eng_image_data_unmap(void *engdata EINA_UNUSED, void *image, void *memory, int l
           }
      }
 
-   ERR("failed to unmap region %p (%u bytes)", memory, length);
+   ERR("failed to unmap region %p (%zu bytes)", slice->mem, slice->len);
    return EINA_FALSE;
 }
 
 static int
-eng_image_data_maps_get(void *engdata EINA_UNUSED, const void *image, void **maps, int *lengths)
+eng_image_data_maps_get(void *engdata EINA_UNUSED, const void *image, const Eina_Rw_Slice **slices)
 {
    Evas_GL_Image_Data_Map *map;
    const Evas_GL_Image *im = image;
@@ -2888,15 +2885,11 @@ eng_image_data_maps_get(void *engdata EINA_UNUSED, const void *image, void **map
 
    if (!im) return -1;
 
-   if (!maps || !lengths)
+   if (!slices)
      return eina_inlist_count(im->maps);
 
    EINA_INLIST_FOREACH(im->maps, map)
-     {
-        maps[k] = map->ptr;
-        lengths[k] = map->size;
-        k++;
-     }
+     slices[k++] = &map->slice;
 
    return k;
 }
diff --git a/src/modules/evas/engines/software_generic/evas_engine.c b/src/modules/evas/engines/software_generic/evas_engine.c
index b684cf0e77..17f9968e5b 100644
--- a/src/modules/evas/engines/software_generic/evas_engine.c
+++ b/src/modules/evas/engines/software_generic/evas_engine.c
@@ -1453,10 +1453,9 @@ eng_image_data_put(void *data, void *image, DATA32 *image_data)
    return im;
 }
 
-static void *
+static const Eina_Rw_Slice *
 eng_image_data_map(void *engdata EINA_UNUSED, void **image,
-                   int *length, int *stride,
-                   int x, int y, int w, int h,
+                   int *stride, int x, int y, int w, int h,
                    Evas_Colorspace cspace, Efl_Gfx_Buffer_Access_Mode mode)
 {
    Eina_Bool cow = EINA_FALSE, to_write = EINA_FALSE;
@@ -1592,8 +1591,8 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
         map->rw = rw;
         map->mode = mode;
         map->baseptr = data;
-        map->ptr = map->baseptr + dst_offset;
-        map->size = dst_len;
+        map->slice.mem = map->baseptr + dst_offset;
+        map->slice.len = dst_len;
         map->stride = dst_stride;
      }
    else
@@ -1607,8 +1606,8 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
              if (!map) return NULL;
 
              map->baseptr = im->image.data8;
-             map->ptr = im->image.data8 + src_offset;
-             map->size = end_offset - src_offset;
+             map->slice.mem = im->image.data8 + src_offset;
+             map->slice.len = end_offset - src_offset;
           }
         else
           {
@@ -1626,8 +1625,8 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
 
              map->allocated = EINA_TRUE;
              map->baseptr = data;
-             map->ptr = data;
-             map->size = size;
+             map->slice.mem = data;
+             map->slice.len = size;
           }
         map->cspace = cspace;
         map->rx = x;
@@ -1639,9 +1638,8 @@ eng_image_data_map(void *engdata EINA_UNUSED, void **image,
 
    im->maps = (RGBA_Image_Data_Map *)
      eina_inlist_prepend(EINA_INLIST_GET(im->maps), EINA_INLIST_GET(map));
-   if (length) *length = map->size;
    if (stride) *stride = map->stride;
-   return map->ptr;
+   return &map->slice;
 }
 
 static void
@@ -1658,13 +1656,13 @@ _image_data_commit(RGBA_Image *im, RGBA_Image_Data_Map *map)
         if (dst_stride == (int) map->stride)
           {
              DBG("unmap commit: single memcpy");
-             memcpy(dst, map->ptr, dst_stride * map->rh);
+             memcpy(dst, map->slice.bytes, dst_stride * map->rh);
           }
         else
           {
              DBG("unmap commit: multiple memcpy");
              for (int k = 0; k < dst_stride; k++)
-               memcpy(dst + k * dst_stride, map->ptr + k * dst_stride, dst_stride);
+               memcpy(dst + k * dst_stride, map->slice.bytes + k * dst_stride, dst_stride);
           }
      }
    else
@@ -1678,7 +1676,7 @@ _image_data_commit(RGBA_Image *im, RGBA_Image_Data_Map *map)
         DBG("unmap commit: convert func (%p)", cs_func);
         if (can_region)
           {
-             cs_func(dst, map->ptr, map->rw, map->rh, map->stride, dst_stride,
+             cs_func(dst, map->slice.mem, map->rw, map->rh, map->stride, dst_stride,
                      ie->flags.alpha, map->cspace, ie->space);
           }
         else
@@ -1690,17 +1688,17 @@ _image_data_commit(RGBA_Image *im, RGBA_Image_Data_Map *map)
 }
 
 static Eina_Bool
-eng_image_data_unmap(void *engdata EINA_UNUSED, void *image, void *memory, int length)
+eng_image_data_unmap(void *engdata EINA_UNUSED, void *image, const Eina_Rw_Slice *slice)
 {
    RGBA_Image_Data_Map *map;
    RGBA_Image *im = image;
 
-   if (!im || !memory)
+   if (!im || !slice)
      return EINA_FALSE;
 
    EINA_INLIST_FOREACH(EINA_INLIST_GET(im->maps), map)
      {
-        if ((map->ptr == memory) && (map->size == length))
+        if ((map->slice.len == slice->len) && (map->slice.mem == slice->mem))
           {
              if (map->allocated)
                {
@@ -1715,12 +1713,12 @@ eng_image_data_unmap(void *engdata EINA_UNUSED, void *image, void *memory, int l
           }
      }
 
-   ERR("failed to unmap region %p (%u bytes)", memory, length);
+   ERR("failed to unmap region %p (%zu bytes)", slice->mem, slice->len);
    return EINA_FALSE;
 }
 
 static int
-eng_image_data_maps_get(void *engdata EINA_UNUSED, const void *image, void **maps, int *lengths)
+eng_image_data_maps_get(void *engdata EINA_UNUSED, const void *image, const Eina_Rw_Slice **slices)
 {
    RGBA_Image_Data_Map *map;
    const RGBA_Image *im = image;
@@ -1728,15 +1726,11 @@ eng_image_data_maps_get(void *engdata EINA_UNUSED, const void *image, void **map
 
    if (!im) return -1;
 
-   if (!maps || !lengths)
+   if (!slices)
      return eina_inlist_count(EINA_INLIST_GET(im->maps));
 
    EINA_INLIST_FOREACH(EINA_INLIST_GET(im->maps), map)
-     {
-        maps[k] = map->ptr;
-        lengths[k] = map->size;
-        k++;
-     }
+     slices[k++] = &map->slice;
 
    return k;
 }