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Simplified wrapX handling

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"Unwrap" the coordinates obtained from transformations and utilize wrapX
capabilities of the sources to handle calculations of TileRanges and
unwrapped tile extents.
This commit is contained in:
Petr Sloup
2015-10-16 09:18:55 +02:00
parent 52a7c5e582
commit a7cde96056
3 changed files with 67 additions and 168 deletions
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src/ol/reproj/reproj.js
+2 -80
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@@ -116,55 +116,12 @@ ol.reproj.render = function(width, height, pixelRatio,
context.scale(pixelRatio, pixelRatio);
var wrapXShiftDistance = sourceExtent ? ol.extent.getWidth(sourceExtent) : 0;
var wrapXType = ol.reproj.WrapXRendering_.NONE;
if (triangulation.getWrapsXInSource() && wrapXShiftDistance > 0) {
// If possible, stitch the sources shifted to solve the wrapX issue here.
// This is not possible if crossing both "dateline" and "prime meridian".
var triangulationSrcExtent = triangulation.calculateSourceExtent();
var triangulationSrcWidth = goog.math.modulo(
ol.extent.getWidth(triangulationSrcExtent), wrapXShiftDistance);
if (triangulationSrcWidth < wrapXShiftDistance / 2) {
wrapXType = ol.reproj.WrapXRendering_.STITCH_SHIFT;
} else {
wrapXType = ol.reproj.WrapXRendering_.STITCH_EXTENDED;
}
}
var sourceDataExtent = ol.extent.createEmpty();
sources.forEach(function(src, i, arr) {
if (wrapXType == ol.reproj.WrapXRendering_.STITCH_SHIFT) {
var srcW = src.extent[2] - src.extent[0];
var srcX = goog.math.modulo(src.extent[0], wrapXShiftDistance);
ol.extent.extend(sourceDataExtent, [srcX, src.extent[1],
srcX + srcW, src.extent[3]]);
} else {
ol.extent.extend(sourceDataExtent, src.extent);
}
ol.extent.extend(sourceDataExtent, src.extent);
});
if (sourceExtent) {
if (wrapXType == ol.reproj.WrapXRendering_.NONE) {
sourceDataExtent[0] = ol.math.clamp(
sourceDataExtent[0], sourceExtent[0], sourceExtent[2]);
sourceDataExtent[2] = ol.math.clamp(
sourceDataExtent[2], sourceExtent[0], sourceExtent[2]);
}
sourceDataExtent[1] = ol.math.clamp(
sourceDataExtent[1], sourceExtent[1], sourceExtent[3]);
sourceDataExtent[3] = ol.math.clamp(
sourceDataExtent[3], sourceExtent[1], sourceExtent[3]);
}
var canvasWidthInUnits;
if (wrapXType == ol.reproj.WrapXRendering_.STITCH_EXTENDED) {
canvasWidthInUnits = 2 * wrapXShiftDistance;
} else {
canvasWidthInUnits = ol.extent.getWidth(sourceDataExtent);
}
var canvasWidthInUnits = ol.extent.getWidth(sourceDataExtent);
var canvasHeightInUnits = ol.extent.getHeight(sourceDataExtent);
var stitchContext = ol.dom.createCanvasContext2D(
Math.round(pixelRatio * canvasWidthInUnits / sourceResolution),
@@ -180,15 +137,7 @@ ol.reproj.render = function(width, height, pixelRatio,
var srcWidth = ol.extent.getWidth(src.extent);
var srcHeight = ol.extent.getHeight(src.extent);
if (wrapXType == ol.reproj.WrapXRendering_.STITCH_SHIFT) {
xPos = goog.math.modulo(xPos, wrapXShiftDistance);
}
stitchContext.drawImage(src.image, xPos, yPos, srcWidth, srcHeight);
if (wrapXType == ol.reproj.WrapXRendering_.STITCH_EXTENDED) {
stitchContext.drawImage(src.image, wrapXShiftDistance + xPos, yPos,
srcWidth, srcHeight);
}
});
var targetTopLeft = ol.extent.getTopLeft(targetExtent);
@@ -227,21 +176,6 @@ ol.reproj.render = function(width, height, pixelRatio,
var u2 = (target[2][0] - targetTopLeft[0]) / targetResolution,
v2 = -(target[2][1] - targetTopLeft[1]) / targetResolution;
var performWrapXShift = wrapXType == ol.reproj.WrapXRendering_.STITCH_SHIFT;
if (wrapXType == ol.reproj.WrapXRendering_.STITCH_EXTENDED) {
var minX = Math.min(x0, x1, x2);
var maxX = Math.max(x0, x1, x2);
performWrapXShift = minX <= sourceExtent[0] ||
(maxX - minX) > wrapXShiftDistance / 2;
}
if (performWrapXShift) {
x0 = goog.math.modulo(x0, wrapXShiftDistance);
x1 = goog.math.modulo(x1, wrapXShiftDistance);
x2 = goog.math.modulo(x2, wrapXShiftDistance);
}
// Shift all the source points to improve numerical stability
// of all the subsequent calculations. The [x0, y0] is used here.
// This is also used to simplify the linear system.
@@ -322,15 +256,3 @@ ol.reproj.render = function(width, height, pixelRatio,
}
return context.canvas;
};
/**
* Type of solution used to solve wrapX in source during rendering.
* @enum {number}
* @private
*/
ol.reproj.WrapXRendering_ = {
NONE: 0,
STITCH_SHIFT: 1,
STITCH_EXTENDED: 2
};