Evas filters: Add transform filter

This is the simplest solution I can come up with for "mirror" effects.
Displacement maps are HARD to generate and use properly, since the buffer
size is unknown until runtime.
Even if we align the map to the text itself (using the padding information),
it's still hard to describe properly how to apply the displacement map, and
to generate it... So let's just add a simple flip operation.

src/Makefile_Evas.am

@@ -374,6 +374,7 @@ lib/evas/filters/evas_filter_curve.c \
 lib/evas/filters/evas_filter_displace.c \
 lib/evas/filters/evas_filter_mask.c \
 lib/evas/filters/evas_filter_parser.c \
+lib/evas/filters/evas_filter_transform.c \
 lib/evas/filters/evas_filter_utils.c
 
 

src/lib/evas/filters/evas_filter.c

@@ -1047,6 +1047,39 @@ end:
    return cmdid;
 }
 
+int
+evas_filter_command_transform_add(Evas_Filter_Context *ctx, void *draw_context,
+                                  int inbuf, int outbuf,
+                                  Evas_Filter_Transform_Flags flags)
+{
+   Evas_Filter_Command *cmd;
+   Evas_Filter_Buffer *in, *out;
+
+   EINA_SAFETY_ON_NULL_RETURN_VAL(ctx, -1);
+
+   in = _filter_buffer_get(ctx, inbuf);
+   out = _filter_buffer_get(ctx, outbuf);
+   if (!in || !out)
+     {
+        ERR("Invalid buffer id: input %d [%p], output %d [%p]",
+            inbuf, in, outbuf, out);
+        return -1;
+     }
+
+   if (in->alpha_only != out->alpha_only)
+     {
+        CRI("Incompatible buffer formats");
+        return -1;
+     }
+
+   cmd = _command_new(ctx, EVAS_FILTER_MODE_TRANSFORM, in, NULL, out);
+   if (!cmd) return -1;
+
+   cmd->transform.flags = flags;
+
+   return cmd->id;
+}
+
 static Eina_Bool
 _fill_cpu(Evas_Filter_Command *cmd)
 {
@@ -1248,6 +1281,9 @@ _filter_command_run(Evas_Filter_Command *cmd)
       case EVAS_FILTER_MODE_BUMP:
         func = evas_filter_bump_map_cpu_func_get(cmd);
         break;
+      case EVAS_FILTER_MODE_TRANSFORM:
+        func = evas_filter_transform_cpu_func_get(cmd);
+        break;
       default:
         CRI("Invalid filter mode.");
         break;

src/lib/evas/filters/evas_filter_private.h

@@ -103,6 +103,11 @@ struct _Evas_Filter_Command
          Eina_Bool compensate : 1; // Compensate for darkening
          //Eina_Bool specular : 1; // Use specular light as well (needs specular_factor > 0)
       } bump;
+
+      struct
+      {
+         Evas_Filter_Transform_Flags flags;
+      } transform;
    };
 
    struct {
@@ -158,6 +163,7 @@ Evas_Filter_Apply_Func   evas_filter_curve_cpu_func_get(Evas_Filter_Command *cmd
 Evas_Filter_Apply_Func   evas_filter_displace_cpu_func_get(Evas_Filter_Command *cmd);
 Evas_Filter_Apply_Func   evas_filter_fill_cpu_func_get(Evas_Filter_Command *cmd);
 Evas_Filter_Apply_Func   evas_filter_mask_cpu_func_get(Evas_Filter_Command *cmd);
+Evas_Filter_Apply_Func   evas_filter_transform_cpu_func_get(Evas_Filter_Command *cmd);
 
 /* Utility functions */
 void _clip_to_target(int *sx, int *sy, int sw, int sh, int ox, int oy, int dw, int dh, int *dx, int *dy, int *rows, int *cols);

src/lib/evas/filters/evas_filter_transform.c

@@ -0,0 +1,65 @@
+#include "evas_filter_private.h"
+
+static Eina_Bool
+_vflip_cpu(Evas_Filter_Command *cmd)
+{
+   size_t datasize, stride;
+   DATA8 *in, *out, *span;
+   int w, h, sy, dy;
+
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd, EINA_FALSE);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd->input, EINA_FALSE);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd->output, EINA_FALSE);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd->input->backing, EINA_FALSE);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd->output->backing, EINA_FALSE);
+
+   w = cmd->input->w;
+   h = cmd->input->h;
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(cmd->output->w == w, EINA_FALSE);
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(cmd->output->h == h, EINA_FALSE);
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(cmd->output->alpha_only == cmd->input->alpha_only, EINA_FALSE);
+
+   in = ((RGBA_Image *) cmd->input->backing)->mask.data;
+   out = ((RGBA_Image *) cmd->output->backing)->mask.data;
+   datasize = cmd->input->alpha_only ? sizeof(DATA8) : sizeof(DATA32);
+   stride = w * datasize;
+
+   if (in == out)
+     {
+        span = malloc(stride);
+        if (!span) return EINA_FALSE;
+     }
+
+   for (sy = 0, dy = h - 1; dy >= 0; sy++, dy--)
+     {
+        DATA8* src = in + stride * sy;
+        DATA8* dst = out + stride * dy;
+
+        if (in == out)
+          {
+             memcpy(span, dst, stride);
+             memcpy(dst, src, stride);
+             memcpy(src, span, stride);
+             if (sy >= (h / 2)) break;
+          }
+        else
+          memcpy(dst, src, stride);
+     }
+
+   return EINA_TRUE;
+}
+
+Evas_Filter_Apply_Func
+evas_filter_transform_cpu_func_get(Evas_Filter_Command *cmd)
+{
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd, NULL);
+
+   switch (cmd->transform.flags)
+     {
+      case EVAS_FILTER_TRANSFORM_VFLIP:
+        return _vflip_cpu;
+      default:
+        CRI("Unknown transform flag %d", (int) cmd->transform.flags);
+        return NULL;
+     }
+}

src/lib/evas/include/evas_filter.h

@@ -14,6 +14,7 @@ typedef enum _Evas_Filter_Channel Evas_Filter_Channel;
 typedef enum _Evas_Filter_Displacement_Flags Evas_Filter_Displacement_Flags;
 typedef enum _Evas_Filter_Bump_Flags Evas_Filter_Bump_Flags;
 typedef enum _Evas_Filter_Fill_Mode Evas_Filter_Fill_Mode;
+typedef enum _Evas_Filter_Transform_Flags Evas_Filter_Transform_Flags;
 
 typedef Eina_Bool (* Evas_Filter_Apply_Func) (Evas_Filter_Command *cmd);
 typedef void (* Evas_Filter_Cb) (Evas_Filter_Context *ctx, void *data);
@@ -30,6 +31,7 @@ enum _Evas_Filter_Mode
    EVAS_FILTER_MODE_FILL,         /**< Fill a buffer with a solid color */
    EVAS_FILTER_MODE_MASK,         /**< Apply Alpha or RGBA texture on image */
    EVAS_FILTER_MODE_BUMP,         /**< Apply bump mapping (light effect) */
+   EVAS_FILTER_MODE_TRANSFORM,    /**< Apply a simple geometrical transformation */
    EVAS_FILTER_MODE_LAST
 };
 
@@ -79,6 +81,11 @@ enum _Evas_Filter_Fill_Mode
    EVAS_FILTER_FILL_MODE_STRETCH_XY         = EVAS_FILTER_FILL_MODE_STRETCH_X | EVAS_FILTER_FILL_MODE_STRETCH_Y
 };
 
+enum _Evas_Filter_Transform_Flags
+{
+   EVAS_FILTER_TRANSFORM_VFLIP = 1
+};
+
 /* Parser stuff (high level API) */
 Evas_Filter_Program     *evas_filter_program_new(const char *name);
 Eina_Bool                evas_filter_program_parse(Evas_Filter_Program *pgm, const char *str);
@@ -213,5 +220,16 @@ int                      evas_filter_command_mask_add(Evas_Filter_Context *ctx,
  */
 int                      evas_filter_command_bump_map_add(Evas_Filter_Context *ctx, void *draw_context, int inbuf, int bumpbuf, int outbuf, float azimuth, float elevation, float depth, float specular_factor, DATA32 black, DATA32 color, DATA32 white, Evas_Filter_Bump_Flags flags, Evas_Filter_Fill_Mode fillmode);
 
+/**
+ * @brief Apply a geometrical transformation to the buffer
+ * @param ctx            Current filter chain
+ * @param draw_context   Current Evas draw context (ignored)
+ * @param inbuf          Input buffer (Alpha or RGBA)
+ * @param outbuf         Output buffer (Alpha or RGBA), same size as inbuf
+ * @param flags          Specifies the operation to apply (eg. vflip)
+ * @return               Filter command ID or -1 in case of error
+ */
+int                      evas_filter_command_transform_add(Evas_Filter_Context *ctx, void *draw_context, int inbuf, int outbuf, Evas_Filter_Transform_Flags flags);
+
 #endif