级别: 中级

            /** Rotate the image.
            *
            * The given image is rotated using the ImageMagick function RotateImage().
            * The angle needs to be specified in degrees. The angle is taken modulo 360
            * degrees; in other words, angles larger than +360 degrees and smaller than
            * -360 degrees are accepted.
            *
            * Positive angles cause the image to be rotated counter-clockwise, and
            * negative angles rotate the image clockwise.
            *
            * NULL is returned if the given image is NULL. If the specified angle is
            * NULL, then the image is returned unchanged.
            */
            IEX_EXTERNC void SQL_API_FN IexRotateImage(
            // input: locator to source image
            SQLUDF_LOCATOR *sourceLocator,
            // input: angle of the rotation
            SQLUDF_DOUBLE *angle,
            // output: locator to target image
            SQLUDF_LOCATOR *targetLocator,
            // null indicators
            SQLUDF_NULLIND *sourceLocator_ind, SQLUDF_NULLIND *angle_ind,
            SQLUDF_NULLIND *targetLocator_ind,
            SQLUDF_TRAIL_ARGS_ALL)
            {
            int rc = IEX_SUCCESS;
            IexError error;
            Image *result = NULL;
            ExceptionInfo exception;
            GetExceptionInfo(&exception);
            // we assume NULL result
            *targetLocator_ind = -1;
            // map the scratchpad
            struct scratchMap *scratch = (struct scratchMap *)SQLUDF_SCRAT->data;
            // clean up when the SQL statement is finished
            if (SQLUDF_CALLT == SQLUDF_FINAL_CALL) {
            goto cleanup;
            }
            // normalize the angle and test if we actually have something to do
            if (SQLUDF_NULL(angle_ind)) {
            *angle = 0.0;
            }
            *angle = fmod(*angle, 360);
            if (*angle == 0.0) {
            *targetLocator = *sourceLocator;
            *targetLocator_ind = 0;
            goto cleanup;
            }
            // read the image data
            rc = IexReadImageToScratchPad(sourceLocator, *sourceLocator_ind,
            scratch, SQLUDF_CALLT, error);
            if (rc || !scratch->image) {
            goto cleanup;
            }
            // rotate the image
            result = RotateImage(scratch->image, *angle, &exception);
            if (!result || IEX_HAVE_MAGICK_EXCEPTION(exception)) {
            IEX_SET_MAGICK_ERROR(exception);
            goto cleanup;
            }
            if (IEX_HAVE_MAGICK_EXCEPTION(result->exception)) {
            IEX_SET_MAGICK_ERROR(result->exception);
            goto cleanup;
            }
            // write the result to the target locator
            rc = IexWriteImageToLocator(result, targetLocator, error);
            if (rc) {
            goto cleanup;
            }
            *targetLocator_ind = 0;
            cleanup:
            DestroyExceptionInfo(&exception);
            if (result) {
            DestroyImage(result);
            }
            IEX_COMMON_CLEANUP;
            }
            

            /** Get the image height.
            *
            * Get the image height from the BLOB (locator) provided as input parameter.
            */
            IEX_EXTERNC
            void SQL_API_FN IexGetImageHeight(
            // input: locator to image
            SQLUDF_LOCATOR *imageLocator,
            // output: height of the image
            SQLUDF_INTEGER *imageHeight,
            // null indicators
            SQLUDF_NULLIND *imageLocator_ind,
            SQLUDF_NULLIND *imageHeight_ind,
            SQLUDF_TRAIL_ARGS_ALL)
            {
            int rc = IEX_SUCCESS;
            IexError error;
            // we assume NULL result
            *imageHeight_ind = -1;
            // map the scratchpad
            struct scratchMap *scratch = (struct scratchMap *)SQLUDF_SCRAT->data;
            rc = InitializeScratchWithPing(imageLocator, *imageLocator_ind, scratch,
            SQLUDF_CALLT, error);
            if (rc || !scratch->image) {
            goto cleanup;
            }
            // we got a result; set output parameter and null indicator
            *imageHeight = scratch->image->magick_rows;
            *imageHeight_ind = 0;
            cleanup:
            IEX_COMMON_CLEANUP;
            }
            

            ########################################################
            # SCRIPT: bldrtn
            # Builds Linux C routines (stored procedures or UDFs)
            # Usage: bldrtn <prog_name> [ <db_name> ]
            # Set DB2PATH to where DB2 will be accessed.
            # The default is the standard instance path.
            DB2PATH=$HOME/sqllib
            # Default compiler/linker settings
            LIB="lib"
            EXTRA_C_FLAGS=""
            # Determine our bitwidth (32 or 64) and hardware platform
            BITWIDTH=`LANG=C db2level | awk '/bits/{print $5}'`
            HARDWAREPLAT=`uname -m`
            if [ $BITWIDTH = "\"32\"" ]
            then
            LIB="lib32"
            fi
            # Set up compiler switches according to the current environment
            if [ "$HARDWAREPLAT" = "x86_64" ] || [ "$HARDWAREPLAT" = "ppc64" ]
            then
            if [ $BITWIDTH = "\"64\"" ]
            then
            EXTRA_C_FLAGS="-m64"
            else
            if [ "$HARDWAREPLAT" != "ppc64" ]
            then
            EXTRA_C_FLAGS="-m32"
            fi
            fi
            fi
            # Set the runtime path.
            EXTRA_LFLAG="-Wl,-rpath,$DB2PATH/$LIB"
            # If an embedded SQL program, precompile and bind it.
            if [ -f $1".sqc" ]
            then
            ./embprep $1 $2
            fi
            # Compile the program.
            for i in IexAttributes.cpp IexCatalog.cpp IexError.cpp IexManipulation.cpp             IexUdfUtils.cpp IexImageBlob.cpp IexDisplay.cpp; do
            gcc $EXTRA_C_FLAGS -fpic -I$DB2PATH/include -c $i -D_REENTRANT
            done
            # Link the program and create a shared library
            gcc $EXTRA_C_FLAGS -shared -o imageudfs *.o $EXTRA_LFLAG -L$DB2PATH/$LIB             -ldb2 -lpthread -ldb2apie -lMagick
            # Copy the shared library to 函数 subdirectory.
            # The user must have write permission to this directory.
            rm -f $DB2PATH/function/imageudfs
            cp imageudfs $DB2PATH/function
            

            $ db2 "connect to <your-database>"
            $ db2 -td@ -f create_blob.sql
            $ db2 -td@ -f create_sqlmm.sql
            $ db2 "connect reset"
            

SI_blur(image BLOB, stdDeviation DOUBLE) &

SI_blur(image BLOB, radius DOUBLE, stdDeviation DOUBLE)

将图像从当前格式转换成指定的格式。

新格式必须是受支持的格式，在编目表 SI_SUPPORTED_FORMATS 中其相应的 ENCODE 标志必须是‘Y’。如果在 Image Extender 编目中没有这种格式，或者其 ENCODE 标志没有被设为‘Y’，那么就会产生异常状况（SQLSTATE 38IUx）

从给定的图像中裁剪出一片区域

如果裁剪的区域超出了图像的范围，就会产生异常状况（SQLSTATE 38IU5）

SI_detectEdges(image BLOB) &

SI_detectEdges(image BLOB, radius DOUBLE)

使用具有指定半径的旋转过滤器探测出图像中的边界

如果这个半径小于 0，那么就会产生一个异常状况（SQLSTATE 38IUx）

将图像中的颜色数量减少到指定的数量。新颜色的计算使用 YUV 颜色空间来进行。

如果颜色数量小于 1，那么将产生一个异常状况（SQLSTATE 38IUx）

SI_monochrome(image BLOB) &

SI_monochrome(image BLOB, threshold DOUBLE)

将给定的图像转换成单色图像。计算每个像素点的亮度，并将其与给定的阈值相比较。如果像素点的亮度低于阈值，则该象素点将变成黑色，反之，就变成白色。阈值越高，图像中就有越多的部分变成黑色。

如果阈值小于 0，或者大于 1，那么将产生一个异常状况（SQLSTATE 38IUx）。

每个像素点的亮度是根据它的 RGB 值计算的。红色部分和蓝色部分的权重占 0.114，绿色部分的权重占 0.587。将 R、G 和 B 三部分的值分别乘于相应的权重，三个积加起来就得到亮度。如果没有给出阈值，或者给出的阈值为 NULL，那么就会隐式地使用缺省的 25,000 作为阈值

SI_resize(image BLOB, width INTEGER, height INTEGER)

SI_resize(image BLOB, width INTEGER, height INTEGER, method VARCHAR)

SI_scale(image BLOB, factor DOUBLE)

SI_scale(image BLOB, factor DOULE, method VARCHAR)

SI_sharpen(image BLOB, stdDeviation DOUBLE) &

SI_sharpen(image BLOB, radius DOUBLE, stdDeviation DOUBLE)

            CREATE TYPE image.SI_StillImage
            AS (
            image_data   BLOB(10M),
            height       INTEGER,
            width        INTEGER,
            format       VARCHAR(128),
            compression  VARCHAR(128),
            color_space  VARCHAR(128)
            )
            INSTANTIABLE
            NOT FINAL
            MODE DB2SQL
            REF USING BIGINT@
            

            ALTER TYPE image.SI_StillImage
            ADD METHOD SI_getHeight()
            RETURNS INTEGER
            SPECIFIC image.SQLMM_getHeight
            LANGUAGE SQL
            DETERMINISTIC
            NO EXTERNAL ACTION
            CONTAINS SQL
            ADD METHOD SI_rotate(angle DOUBLE)
            RETURNS INTEGER
            SPECIFIC image.SQLMM_rotate
            SELF AS RESULT
            LANGUAGE SQL
            DETERMINISTIC
            NO EXTERNAL ACTION
            CONTAINS SQL@
            CREATE METHOD SI_getHeight()
            FOR image.SI_StillImage
            RETURN SELF..height@
            CREATE METHOD SI_rotate(angle DOUBLE)
            FOR image.SI_StillImage
            RETURN SELECT SELF..image_data(result.image)..
            height(attr.height)..width(attr.width)..
            format(attr.format)..compression(attr.compression)..
            color_space(attr.colorSpace)
            FROM   TABLE ( VALUES ( SI_rotate(SELF..image_data, angle) ) )
            AS result(image),
            TABLE ( SI_getImageAttr(result.image) ) AS attr
            WHERE  SELF IS NOT NULL@
            

            CREATE FUNCTION image.SI_StillImage(image BLOB)
            RETURNS image.SI_StillImage
            SPECIFIC image.SI_StillImage
            LANGUAGE SQL
            DETERMINISTIC
            NO ExTERNAL ACTION
            CONTAINS SQL
            RETURN SELECT SI_StillImage()..image_data(image)..
            height(attr.height)..width(attr.width)..
            format(attr.format)..compression(attr.compression)..
            color_space(attr.colorSpace)
            FROM   TABLE ( SI_getImageAttr(image) ) AS attr
            WHERE  image IS NOT NULL@
            

            IMAGE.SI_SUPPORTED_FORMATS(
            format       VARCHAR(128),
            decode       CHARACTER(1),
            encode       CHARACTER(1),
            description  VARCHAR(254)
            )
            

            $ db2 "connect to <your-database>"
            $ db2 -td@ -f create_load.sql
            $ db2 -td@ -f create_display.sql
            $ db2 "connect reset"
            

            $ db2 -td@
            db2 => SELECT COUNT(*) FROM image.si_supported_formats@
            1
            -----------
            147
            1 record(s) selected.
            db2 => SELECT * FROM image.si_supported_formats FETCH FIRST 13 ROWS ONLY@
            FORMAT     ENCODE DECODE DESCRIPTION
            ---------- ------ ------ --------------------------------------
            A          Y      Y      Raw alpha samples
            ART        N      Y      PFS: 1st Publisher
            AVI        N      Y      Microsoft® Audio/Visual Interleaved
            AVS        Y      Y      AVS X image
            B          Y      Y      Raw blue samples
            BMP        Y      Y      Microsoft Windows® bitmap image
            BMP2       Y      N      Microsoft Windows bitmap image v2
            BMP3       Y      N      Microsoft Windows bitmap image v3
            C          Y      Y      Raw cyan samples
            CAPTION    N      Y      Image caption
            CIN        Y      Y      Cineon Image File
            CIP        Y      N      Cisco IP phone image format
            CLIP       Y      N      Image Clip Mask
            13 record(s) selected.
            

            $ db2 -td@
            db2 => SET CURRENT FUNCTION PATH = image, CURRENT FUNCTION PATH@
            db2 => VALUES SI_getHeight(SI_loadImage('/home/stolze/test_1.jpg'))@
            1
            -----------
            128
            1 record(s) selected.
            db2 => VALUES SI_getFormat(SI_loadImage('/home/stolze/test_2.gif'))@
            1
            ------------------------
            GIF
            1 record(s) selected.
            db2 => VALUES SI_StillImage(
            db2 (cont.) => SI_loadImage('/home/stolze/test_2.gif'))..SI_getWidth()@
            1
            -----------
            481
            1 record(s) selected.
            db2 => VALUES SI_StillImage(
            db2 (cont.) => SI_loadImage('/home/stolze/test_1.jpg'))..SI_getYResolution()@
            1
            ------------------------
            +1.11000000000000E+002
            1 record(s) selected.
            

            $ db2 -td@
            db2 => SET CURRENT FUNCTION PATH = image, CURRENT FUNCTION PATH@
            db2 => CREATE TABLE t1 ( id INTEGER, img BLOB(10M) )@
            db2 => INSERT INTO t1 VALUES ( 1, SI_loadImage('/home/stolze/test_1.jpg') )@
            db2 => UPDATE t1 SET img = SI_rotate(img, 45) WHERE id = 1@
            db2 => SELECT SI_exportImage(img, '/home/stolze/test_1.jpg') FROM t1 WHERE id = 1@
            1
            -----------
            10237
            1 record(s) selected.
            db2 => QUIT@
            $ xv /home/stolze/res_1.jpg
            

            $ db2 -td@
            db2 => SET CURRENT FUNCTION PATH = image, CURRENT FUNCTION PATH@
            db2 => CREATE TABLE t2 ( id INTEGER, img image.SI_StillImage )@
            db2 => INSERT INTO t2 VALUES ( 1, SI_StillImage(
            db2 (cont.) => SI_loadImage('/home/stolze/test_2.gif')) )@
            db2 => SELECT img..SI_shear(10, 0)..SI_roll(50, 0)..SI_display()
            db2 (cont.) => FROM t2 WHERE id = 1@
            1
            -----------
            0
            1 record(s) selected.