racket/collects/2htdp/image.ss

116 lines
2.6 KiB
Scheme

#lang scheme/base
#|
Need to test copy & paste. Also test that if the "if"
expression in image-snipclass%'s read
method returns #f, then you get a black circle out.
---
improvments/changes wrt to htdp/image:
- copying and pasting does not introduce jaggies
- equal comparisions are more efficient
- added rotation & scaling
- got rid of pinholes (see the new overlay, beside, and above functions)
- a bunch of new polygon functions
Equality change: equality is now based on the structure of the construction of the picture.
This means that some equalities that were there before are no longer true. For example,
in the old library, these two images are the same:
(overlay/xy (rectangle 100 10 'solid 'red)
0
10
(rectangle 100 10 'solid 'red))
(rectangle 100 20 'solid 'red)
... and why aren't they the same again....?!
todo: sort out wxme library support (loading in text mode).
------------
From Matthias: (to use to compare with this library)
You asked about exercises and code snippets for HtDP/2e yesterday. I actually do have a bunch of stuff in
svn: 2HtDP/SampleCode/
and they all have good sample contracts. (It is amazing what we can do with kids who have just a few weeks of cs down; I would have never dared to write an editor after six weeks in Algol.)
|#
(require "../mrlib/image-core.ss"
"private/image-more.ss"
"private/img-err.ss"
htdp/error)
(provide overlay
overlay/align
overlay/xy
underlay
underlay/align
underlay/xy
beside
beside/align
above
above/align
crop
rotate
frame
place-image
place-image/align
scale
scale/xy
circle
ellipse
rectangle
square
rhombus
regular-polygon
polygon
star
star-polygon
triangle
isosceles-triangle
right-triangle
line
add-line
add-curve
scene+line
scene+curve
text
text/font
bitmap
x-place?
y-place?
image?
mode?
angle?
side-count?
image-color?
pen-style?
pen-cap?
pen-join?
(rename-out [build-color make-color])
color-red color-blue color-green color? color
(rename-out [build-pen make-pen])
pen-color pen-width pen-style pen-cap pen-join pen
image-width
image-height
image-baseline)