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IRIX 6.2 Applications 1996 August
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Silicon_Graphics_812-0542-002.iso
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relnotes
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imgtools
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ch5.z
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ch5
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1996-08-03
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5. _K_n_o_w_n__P_r_o_b_l_e_m_s__a_n_d__W_o_r_k_a_r_o_u_n_d_s
This chapter lists known problems in this release of IRIS
ImageVision Utilities.
5.1 _I_m_g_c_o_p_y _d_e_p_r_e_c_a_t_e_s _t_r_a_n_s_p_o_s_e_d _c_o_o_r_d_i_n_a_t_e _s_p_a_c_e_s _b_y
_d_e_f_a_u_l_t
When copying a source image to a destination image, imgcopy
will translate transposed coordinate systems (column-major
stored) in a source image to the corresponding non-
transposed coodinate system in the destination image. I.e.
if the source image has a right-upper coordinate system, the
destination image will have an upper-right coordinate
system. This is done because many common image file readers
cannot read images stored in transposed coordinate spaces -
the IL does not share this problem. This default behavior
can be overridden by specifying an explicit coordinate
system (-c_x_x) on the command line.
5.2 _I_m_g_c_o_p_y__d_o_e_s__n_o_t__p_r_e_s_e_r_v_e__s_o_u_r_c_e__i_m_a_g_e__p_a_g_e__s_i_z_e
By default imgcopy will invent a new page size for the
destination image. If you wish to preserve the page size of
the source image you must explicitly specify it on the
command line (-p_x,_y,_z,_c).
5.3 _I_m_g_c_o_p_y _o_f _l_a_r_g_e _i_m_a_g_e_s _w_i_t_h _t_r_a_n_s_p_o_s_e_d _c_o_o_r_d_i_n_a_t_e
_s_y_s_t_e_m_s _c_a_n _b_e _s_l_o_w
If you copy a large transposed image with imgcopy, by
default imgcopy will change the coordinate system of the
destination to be untransposed. For images whose pages are
colomn and row stripes, this means that the entire source
image (columns) will have to be read in order to write a
single destination row. If the image is very large, the
first source columns are likely to have already been paged
out and thus require rereading in order to write the second
destination row, etc. You can force imgcopy to retain the
original transposed coordinate system if you know the
resulting image won't be problematic for your application.
Alternatively you can try to increase the size of the IL's
cache via the IL_CACHE_FRACTION or IL_CACHE_SIZE environment
variables).
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5.4 _I_L _A_p_p_l_i_c_a_t_i_o_n_s _S_o_m_e_t_i_m_e_s _P_r_i_n_t `_H_a_n_g_u_p' _w_h_e_n
_I_n_t_e_r_r_u_p_t_e_d
When an IL application is interrupted sometimes a child
thread will exit before the original main thread. When this
happens the main thread will be sent a SIGHUP and the shell
will print the message "Hangup" on the console. This is
harmless.
5.5 _R_e_a_d_i_n_g__D_a_m_a_g_e_d__G_I_F__F_i_l_e_s
The IL GIF image file format reader is very unforgiving of
errors in GIF files. A temporary work around is to use an
alternate image file display program like _x_v which is
currently more tollerant of file format errors.
5.6 _I_m_a_g_e__V_i_e_w__D_e_t_a_i_l__V_i_e_w
Image View detail view has a small square showing the pixel
of interest. On some low-end systems, the rectangle is
filled. If the detail view is resized, the rectangle can
become misaligned.
5.7 _I_m_a_g_e__W_o_r_k_s__U_n_d_o
Image Works only supports 2 levels of undo. Only the last 2
operations can be undone.
5.8 _I_m_a_g_e__W_o_r_k_s__R_e_m_o_t_e__D_i_s_p_l_a_y__P_r_o_b_l_e_m_s
When imgworks is run with a non-local display it sometimes
misses scraps of its display when responding to an expose
event. This is most evident when moving an obscuring window
slightly. To work around this problem iconify and deiconify
imgworks.
5.9 _I_m_a_g_e _W_o_r_k_s _C_r_o_p/_S_c_a_l_e/_S_t_r_e_t_c_h _H_a_n_d_l_e_s _D_o_n'_t _R_e_d_r_a_w
_P_r_o_p_e_r_l_y
If you crop/scale/stretch beyond the image, the resulting
image will not be properly displayed. To work around this
problem iconify and deiconify imgworks. Imgworks no longer
by default saves images with an alpha channel. Images are
saved in their original color models unless the image was
originally grayscale and was colorized in imgworks. In this
case imgworks saves the image as RGB. Also if the image was
original in color but was transformed to grayscale in
imgworks. In this case imgworks saves the image as
grayscale.
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