TGA: Add support for writing RLE data

Tests/images/tga/common/readme.txt

@@ -0,0 +1,12 @@
+Images in this directory were created with GIMP.
+
+TGAs have names in the following format:
+
+  {width}x{height}_{mode}_{origin}_{compression}.tga
+
+Where:
+  mode is PIL mode in lower case (L, P, RGB, etc.)
+  origin:
+    "bl" - bottom left
+    "tl" - top left
+  compression is either "raw" or "rle"

Tests/test_file_tga.py

@@ -1,10 +1,76 @@
+import os
+from glob import glob
+from itertools import product
+
 from helper import unittest, PillowTestCase
 
 from PIL import Image
 
 
+_TGA_DIR = os.path.join("Tests", "images", "tga")
+_TGA_DIR_COMMON = os.path.join(_TGA_DIR, "common")
+
+
 class TestFileTga(PillowTestCase):
 
+    _MODES = ("L", "P", "RGB", "RGBA")
+    _ORIGINS = ("tl", "bl")
+
+    _ORIGIN_TO_ORIENTATION = {
+        "tl": 1,
+        "bl": -1
+    }
+
+    def test_sanity(self):
+        for mode in self._MODES:
+            png_paths = glob(
+                os.path.join(
+                    _TGA_DIR_COMMON, "*x*_{}.png".format(mode.lower())))
+
+            for png_path in png_paths:
+                reference_im = Image.open(png_path)
+                self.assertEqual(reference_im.mode, mode)
+
+                path_no_ext = os.path.splitext(png_path)[0]
+                for origin, rle in product(self._ORIGINS, (True, False)):
+                    tga_path = "{}_{}_{}.tga".format(
+                        path_no_ext, origin, "rle" if rle else "raw")
+
+                    original_im = Image.open(tga_path)
+                    if rle:
+                        self.assertEqual(
+                            original_im.info["compression"], "tga_rle")
+                    self.assertEqual(
+                        original_im.info["orientation"],
+                        self._ORIGIN_TO_ORIENTATION[origin])
+                    if mode == "P":
+                        self.assertEqual(
+                            original_im.getpalette(),
+                            reference_im.getpalette())
+
+                    self.assert_image_equal(original_im, reference_im)
+
+                    # Generate a new test name every time so the
+                    # test will not fail with permission error
+                    # on Windows.
+                    test_file = self.tempfile("temp.tga")
+
+                    original_im.save(test_file, rle=rle)
+                    saved_im = Image.open(test_file)
+                    if rle:
+                        self.assertEqual(
+                            saved_im.info["compression"],
+                            original_im.info["compression"])
+                    self.assertEqual(
+                        saved_im.info["orientation"],
+                        original_im.info["orientation"])
+                    if mode == "P":
+                        self.assertEqual(
+                            saved_im.getpalette(),
+                            original_im.getpalette())
+
+                    self.assert_image_equal(saved_im, original_im)
+
     def test_id_field(self):
         # tga file with id field
         test_file = "Tests/images/tga_id_field.tga"

setup.py

@@ -46,10 +46,10 @@ _LIB_IMAGING = (
     "Negative", "Offset", "Pack", "PackDecode", "Palette", "Paste", "Quant",
     "QuantOctree", "QuantHash", "QuantHeap", "PcdDecode", "PcxDecode",
     "PcxEncode", "Point", "RankFilter", "RawDecode", "RawEncode", "Storage",
-    "SgiRleDecode", "SunRleDecode", "TgaRleDecode", "Unpack", "UnpackYCC",
-    "UnsharpMask", "XbmDecode", "XbmEncode", "ZipDecode", "ZipEncode",
-    "TiffDecode", "Jpeg2KDecode", "Jpeg2KEncode", "BoxBlur", "QuantPngQuant",
-    "codec_fd")
+    "SgiRleDecode", "SunRleDecode", "TgaRleDecode", "TgaRleEncode", "Unpack",
+    "UnpackYCC", "UnsharpMask", "XbmDecode", "XbmEncode", "ZipDecode",
+    "ZipEncode", "TiffDecode", "Jpeg2KDecode", "Jpeg2KEncode", "BoxBlur",
+    "QuantPngQuant", "codec_fd")
 
 DEBUG = False
 

src/PIL/TgaImagePlugin.py

@@ -147,6 +147,11 @@ def _save(im, fp, filename):
     except KeyError:
         raise IOError("cannot write mode %s as TGA" % im.mode)
 
+    rle = im.encoderinfo.get("rle", False)
+
+    if rle:
+        imagetype += 8
+
     if colormaptype:
         colormapfirst, colormaplength, colormapentry = 0, 256, 24
     else:
@@ -177,8 +182,14 @@ def _save(im, fp, filename):
     if colormaptype:
         fp.write(im.im.getpalette("RGB", "BGR"))
 
-    ImageFile._save(
-        im, fp, [("raw", (0, 0) + im.size, 0, (rawmode, 0, orientation))])
+    if rle:
+        ImageFile._save(
+            im,
+            fp,
+            [("tga_rle", (0, 0) + im.size, 0, (rawmode, orientation))])
+    else:
+        ImageFile._save(
+            im, fp, [("raw", (0, 0) + im.size, 0, (rawmode, 0, orientation))])
 
     # write targa version 2 footer
     fp.write(b"\000" * 8 + b"TRUEVISION-XFILE." + b"\000")

src/_imaging.c

@@ -3594,6 +3594,7 @@ extern PyObject* PyImaging_JpegEncoderNew(PyObject* self, PyObject* args);
 extern PyObject* PyImaging_Jpeg2KEncoderNew(PyObject* self, PyObject* args);
 extern PyObject* PyImaging_PcxEncoderNew(PyObject* self, PyObject* args);
 extern PyObject* PyImaging_RawEncoderNew(PyObject* self, PyObject* args);
+extern PyObject* PyImaging_TgaRleEncoderNew(PyObject* self, PyObject* args);
 extern PyObject* PyImaging_XbmEncoderNew(PyObject* self, PyObject* args);
 extern PyObject* PyImaging_ZipEncoderNew(PyObject* self, PyObject* args);
 extern PyObject* PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args);
@@ -3661,6 +3662,7 @@ static PyMethodDef functions[] = {
     {"sgi_rle_decoder", (PyCFunction)PyImaging_SgiRleDecoderNew, 1},
     {"sun_rle_decoder", (PyCFunction)PyImaging_SunRleDecoderNew, 1},
     {"tga_rle_decoder", (PyCFunction)PyImaging_TgaRleDecoderNew, 1},
+    {"tga_rle_encoder", (PyCFunction)PyImaging_TgaRleEncoderNew, 1},
     {"xbm_decoder", (PyCFunction)PyImaging_XbmDecoderNew, 1},
     {"xbm_encoder", (PyCFunction)PyImaging_XbmEncoderNew, 1},
 #ifdef HAVE_LIBZ

src/encode.c

@@ -492,6 +492,38 @@ PyImaging_RawEncoderNew(PyObject* self, PyObject* args)
 }
 
 
+/* -------------------------------------------------------------------- */
+/* TGA                                                                  */
+/* -------------------------------------------------------------------- */
+
+PyObject*
+PyImaging_TgaRleEncoderNew(PyObject* self, PyObject* args)
+{
+    ImagingEncoderObject* encoder;
+
+    char *mode;
+    char *rawmode;
+    int ystep = 1;
+
+    if (!PyArg_ParseTuple(args, "ss|i", &mode, &rawmode, &ystep))
+        return NULL;
+
+    encoder = PyImaging_EncoderNew(0);
+    if (encoder == NULL)
+        return NULL;
+
+    if (get_packer(encoder, mode, rawmode) < 0)
+        return NULL;
+
+    encoder->encode = ImagingTgaRleEncode;
+
+    encoder->state.ystep = ystep;
+
+    return (PyObject*) encoder;
+}
+
+
+
 /* -------------------------------------------------------------------- */
 /* XBM                                                                  */
 /* -------------------------------------------------------------------- */

src/libImaging/Imaging.h

@@ -473,6 +473,8 @@ extern int ImagingSunRleDecode(Imaging im, ImagingCodecState state,
                                UINT8* buffer, int bytes);
 extern int ImagingTgaRleDecode(Imaging im, ImagingCodecState state,
                                UINT8* buffer, int bytes);
+extern int ImagingTgaRleEncode(Imaging im, ImagingCodecState state,
+                               UINT8* buffer, int bytes);
 extern int ImagingXbmDecode(Imaging im, ImagingCodecState state,
                             UINT8* buffer, int bytes);
 extern int ImagingXbmEncode(Imaging im, ImagingCodecState state,

src/libImaging/TgaRleEncode.c

@@ -0,0 +1,153 @@
+
+#include "Imaging.h"
+
+#include <assert.h>
+#include <string.h>
+
+
+static int comparePixels(const UINT8* buf, int x, int bytesPerPixel)
+{
+    buf += x * bytesPerPixel;
+    return memcmp(buf, buf + bytesPerPixel, bytesPerPixel) == 0;
+}
+
+
+int
+ImagingTgaRleEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
+{
+    UINT8* dst;
+    int bytesPerPixel;
+
+    if (state->state == 0) {
+        if (state->ystep < 0) {
+            state->ystep = -1;
+            state->y = state->ysize - 1;
+        } else
+            state->ystep = 1;
+
+        state->state = 1;
+    }
+
+    dst = buf;
+    bytesPerPixel = (state->bits + 7) / 8;
+
+    while (1) {
+        int flushCount;
+
+        /*
+         * state->count is the numbers of bytes in the packet,
+         * excluding the 1-byte descriptor.
+         */
+        if (state->count == 0) {
+            UINT8* row;
+            UINT8 descriptor;
+            int startX;
+
+            assert(state->x <= state->xsize);
+
+            /* Make sure we have space for the descriptor. */
+            if (bytes < 1)
+                break;
+
+            if (state->x == state->xsize) {
+                state->x = 0;
+
+                state->y += state->ystep;
+                if (state->y < 0 || state->y >= state->ysize) {
+                    state->errcode = IMAGING_CODEC_END;
+                    break;
+                }
+            }
+
+            if (state->x == 0)
+                state->shuffle(
+                    state->buffer,
+                    (UINT8*)im->image[state->y + state->yoff]
+                        + state->xoff * im->pixelsize,
+                    state->xsize);
+
+            row = state->buffer;
+
+            /* Start with a raw packet for 1 px. */
+            descriptor = 0;
+            startX = state->x;
+            state->count = bytesPerPixel;
+
+            if (state->x + 1 < state->xsize) {
+                int maxLookup;
+                int isRaw;
+
+                isRaw = !comparePixels(row, state->x, bytesPerPixel);
+                ++state->x;
+
+                /*
+                 * A packet can contain up to 128 pixels;
+                 * 2 are already behind (state->x points to
+                 * the second one).
+                 */
+                maxLookup = state->x + 126;
+                /* A packet must not span multiple rows. */
+                if (maxLookup > state->xsize - 1)
+                    maxLookup = state->xsize - 1;
+
+                if (isRaw) {
+                    while (state->x < maxLookup)
+                        if (!comparePixels(row, state->x, bytesPerPixel))
+                            ++state->x;
+                        else {
+                            /* Two identical pixels will go to RLE packet. */
+                            --state->x;
+                            break;
+                        }
+
+                    state->count += (state->x - startX) * bytesPerPixel;
+                } else {
+                    descriptor |= 0x80;
+
+                    while (state->x < maxLookup)
+                        if (comparePixels(row, state->x, bytesPerPixel))
+                            ++state->x;
+                        else
+                            break;
+                }
+            }
+
+            /*
+             * state->x currently points to the last pixel to be
+             * included in the packet. The pixel count in the
+             * descriptor is 1 less than actual number of pixels in
+             * the packet, that is, state->x == startX if we encode
+             * only 1 pixel.
+             */
+            descriptor += state->x - startX;
+            *dst++ = descriptor;
+            --bytes;
+
+            /* Advance to past-the-last encoded pixel. */
+            ++state->x;
+        }
+
+        assert(bytes >= 0);
+        assert(state->count > 0);
+        assert(state->x > 0);
+        assert(state->count <= state->x * bytesPerPixel);
+
+        if (bytes == 0)
+            break;
+
+        flushCount = state->count;
+        if (flushCount > bytes)
+            flushCount = bytes;
+
+        memcpy(
+            dst,
+            state->buffer + (state->x * bytesPerPixel - state->count),
+            flushCount);
+        dst += flushCount;
+        bytes -= flushCount;
+
+        state->count -= flushCount;
+    }
+
+    return dst - buf;
+}